EN(STI)(diag)-96

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

19.Diagnostic Procedure with Diagnostic Trouble Code (DTC)

A: DTC P000A A CAMSHAFT POSITION SLOW RESPONSE (BANK 1)

NOTE:

For the diagnostic procedure, refer to DTC P0011. <Ref. to EN(STI)(diag)-97, DTC P0011 INTAKE CAM-

SHAFT POSITION - TIMING OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 1), Diagnostic Pro-

cedure with Diagnostic Trouble Code (DTC).>

B: DTC P000B B CAMSHAFT POSITION SLOW RESPONSE (BANK 1)

NOTE:

For the diagnostic procedure, refer to DTC P0014. <Ref. to EN(STI)(diag)-98, DTC P0014 EXHAUST AVCS

SYSTEM 1 (RANGE/PERFORMANCE), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

C: DTC P000C A CAMSHAFT POSITION SLOW RESPONSE (BANK 2)

NOTE:

For the diagnostic procedure, refer to DTC P0021. <Ref. to EN(STI)(diag)-103, DTC P0021 INTAKE CAM-

SHAFT POSITION - TIMING OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 2), Diagnostic Pro-

cedure with Diagnostic Trouble Code (DTC).>

D: DTC P000D B CAMSHAFT POSITION SLOW RESPONSE (BANK 2)

NOTE:

For the diagnostic procedure, refer to DTC P0024. <Ref. to EN(STI)(diag)-104, DTC P0024 EXHAUST

AVCS SYSTEM 2 (RANGE/PERFORMANCE), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

15WRX_STI_US_EN.book 96 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-97

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

E: DTC P0011 INTAKE CAMSHAFT POSITION - TIMING OVER-ADVANCED OR

SYSTEM PERFORMANCE (BANK 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-16, DTC P0011 INTAKE CAMSHAFT POSITION - TIMING

OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 1), Diagnostic Trouble Code (DTC) Detecting

Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the value of «VVT Adv. Ang. Amount

R» using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «VVT Adv. Ang.

Amount R» approx. 0 deg?

Go to step 2. Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Intake camshaft

(dirt, damage of

camshaft)

2 CHECK CURRENT DATA.

1) Drive with acceleration and deceleration at

80 km/h (50 MPH) or less.

NOTE:

Drive to an extent that the duty output of oil flow

control solenoid valve increases.

2) Read the values of «OCV Duty R» and

«VVT Adv. Ang. Amount R» using the Subaru

Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

When the value of «OCV Duty

R» increases more than 10%,

is the value of «VVT Adv. Ang.

Amount R» approx. 0 deg?

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Intake camshaft

(dirt, damage of

camshaft)

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

15WRX_STI_US_EN.book 97 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-98

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

F: DTC P0014 EXHAUST AVCS SYSTEM 1 (RANGE/PERFORMANCE)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-17, DTC P0014 EXHAUST AVCS SYSTEM 1 (RANGE/

PERFORMANCE), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the value of «Exh. VVT Retard Ang.

R» using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Exh. VVT

Retard Ang. R» approx. 0 deg?

Go to step 2. Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Exhaust cam-

shaft (dirt, dam-

age of camshaft)

2 CHECK CURRENT DATA.

1) Drive with acceleration and deceleration at

80 km/h (50 MPH) or less.

NOTE:

Drive to an extent that the duty output of oil flow

control solenoid valve increases.

2) Read the values of «Exh. OCV Duty R» and

«Exh. VVT Retard Ang. R» using the Subaru

Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

When the value of «Exh. OCV

Duty R» increases more than

10%, is the value of «Exh. VVT

Retard Ang. R» approx. 0 deg?

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Exhaust cam-

shaft (dirt, dam-

age of camshaft)

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

15WRX_STI_US_EN.book 98 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-99

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

G: DTC P0016 CRANKSHAFT POSITION - CAMSHAFT POSITION CORRELA-

TION (BANK1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-18, DTC P0016 CRANKSHAFT POSITION - CAMSHAFT

POSITION CORRELATION (BANK1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the values of «VVT Adv. Ang. Amount

R» and «OCV Duty R» using the Subaru Select

Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «VVT Adv. Ang.

Amount R» approx. 0 deg, and

the value of «OCV Duty R»

approx. 10%?

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Intake camshaft

(dirt, damage of

camshaft)

• Timing belt

(matching of timing

mark)

15WRX_STI_US_EN.book 99 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-100

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

H: DTC P0017 CRANK AND CAM TIMING B SYSTEM FAILURE (BANK 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-20, DTC P0017 CRANK AND CAM TIMING B SYSTEM

FAILURE (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the values of «Exh. VVT Retard Ang.

R» and «Exh. OCV Duty R» using the Subaru

Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Exh. VVT

Retard Ang. R» approx. 0 deg,

and the value of «Exh. OCV

Duty R» approx. 10%?

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Exhaust cam-

shaft (dirt, dam-

age of camshaft)

• Timing belt

(matching of timing

mark)

15WRX_STI_US_EN.book 100 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-101

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

I: DTC P0018 CRANKSHAFT POSITION - CAMSHAFT POSITION CORRELA-

TION (BANK2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-21, DTC P0018 CRANKSHAFT POSITION - CAMSHAFT

POSITION CORRELATION (BANK2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the values of «VVT Adv. Ang. Amount

L» and «OCV Duty L» using the Subaru Select

Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «VVT Adv. Ang.

Amount L» approx. 0 deg, and

the value of «OCV Duty L»

approx. 10%?

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Intake camshaft

(dirt, damage of

camshaft)

• Timing belt

(matching of timing

mark)

15WRX_STI_US_EN.book 101 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-102

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

J: DTC P0019 CRANK AND CAM TIMING B SYSTEM FAILURE (BANK 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-21, DTC P0019 CRANK AND CAM TIMING B SYSTEM

FAILURE (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the values of «Exh. VVT Retard Ang.

L» and «Exh. OCV Duty L» using the Subaru

Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Exh. VVT

Retard Ang. L» approx. 0 deg,

and the value of «Exh. OCV

Duty L» approx. 10%?

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Exhaust cam-

shaft (dirt, dam-

age of camshaft)

• Timing belt

(matching of timing

mark)

15WRX_STI_US_EN.book 102 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-103

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

K: DTC P0021 INTAKE CAMSHAFT POSITION - TIMING OVER-ADVANCED OR

SYSTEM PERFORMANCE (BANK 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-21, DTC P0021 INTAKE CAMSHAFT POSITION - TIMING

OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 2), Diagnostic Trouble Code (DTC) Detecting

Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the value of «VVT Adv. Ang. Amount

L» using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «VVT Adv. Ang.

Amount L» approx. 0 deg?

Go to step 2. Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Intake camshaft

(dirt, damage of

camshaft)

2 CHECK CURRENT DATA.

1) Drive with acceleration and deceleration at

80 km/h (50 MPH) or less.

NOTE:

Drive to an extent that the duty output of oil flow

control solenoid valve increases.

2) Read the values of «OCV Duty L» and «VVT

Adv. Ang. Amount L» using the Subaru Select

Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

When the value of «OCV Duty

L» increases more than 10%, is

the value of «VVT Adv. Ang.

Amount L» approx. 0 deg?

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Intake camshaft

(dirt, damage of

camshaft)

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

15WRX_STI_US_EN.book 103 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-104

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

L: DTC P0024 EXHAUST AVCS SYSTEM 2 (RANGE/PERFORMANCE)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-21, DTC P0024 EXHAUST AVCS SYSTEM 2 (RANGE/

PERFORMANCE), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Read the value of «Exh. VVT Retard Ang.

L» using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Exh. VVT

Retard Ang. L» approx. 0 deg?

Go to step 2. Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Exhaust cam-

shaft (dirt, dam-

age of camshaft)

2 CHECK CURRENT DATA.

1) Drive with acceleration and deceleration at

80 km/h (50 MPH) or less.

NOTE:

Drive to an extent that the duty output of oil flow

control solenoid valve increases.

2) Read the values of «Exh. OCV Duty L» and

«Exh. VVT Retard Ang. L» using the Subaru

Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

When the value of «Exh. OCV

Duty L» increases more than

10%, is the value of «Exh. VVT

Retard Ang. L» approx. 0 deg?

Check the follow-

ing item and repair

or replace if neces-

sary.

• Oil pipe (clog)

• Oil flow control

solenoid valve

(clog or dirt of oil

routing, setting of

spring)

• Exhaust cam-

shaft (dirt, dam-

age of camshaft)

Perform the follow-

ing procedures,

and clean the oil

routing.

Replace the

engine oil and idle

the engine for 5

minutes, and then

replace the oil filter

and engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.> <Ref. to

LU(STI)-29,

Engine Oil Filter.>

15WRX_STI_US_EN.book 104 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-105

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

M: DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-22, DTC P0030 HO2S HEATER CONTROL CIRCUIT

(BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 105 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-106

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Start and warm up the engine.

2) Turn the ignition switch to OFF.

3) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

4) Measure the resistance of harness between

ECM connector and front oxygen (A/F) sensor

connector.

Connector & terminal

(B136) No. 5 — (B379) No. 2:

(B136) No. 6 — (B379) No. 2:

(B136) No. 18 — (B379) No. 3:

(B136) No. 19 — (B379) No. 4:

Is the resistance less than 1 Ω? Go to step 2. Repair the open

circuit of harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

2 CHECK FRONT OXYGEN (A/F) SENSOR.

Measure the resistance between front oxygen

(A/F) sensor terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 2 —

3 Ω?

Go to step 3. Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

3 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and front oxygen

(A/F) sensor connector.

Is there poor contact of ECM or

front oxygen (A/F) sensor con-

nector?

Repair the poor

contact of ECM or

front oxygen (A/F)

sensor connector.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 106 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-107

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

N: DTC P0031 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-23, DTC P0031 HO2S HEATER CONTROL CIRCUIT LOW

(BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 107 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-108

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY TO FRONT OXY-

GEN (A/F) SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from front oxy-

gen (A/F) sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between front oxygen

(A/F) sensor connector and engine ground.

Connector & terminal

(B379) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the power

supply line.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

A/F, oxygen sen-

sor relay and front

oxygen (A/F) sen-

sor connector

• Poor contact of

A/F, oxygen sen-

sor relay connector

• Malfunction of A/

F, oxygen sensor

relay

2 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and front oxygen (A/F) sensor connector.

Connector & terminal

(B136) No. 5 — (B379) No. 2:

(B136) No. 6 — (B379) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the open

circuit of harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

3 CHECK GROUND CIRCUIT FOR ECM.

Measure the resistance of harness between

ECM connector and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:

(B134) No. 4 — Chassis ground:

(B134) No. 6 — Chassis ground:

(B137) No. 1 — Chassis ground:

(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

coupling connector

4 CHECK FRONT OXYGEN (A/F) SENSOR.

Measure the resistance between front oxygen

(A/F) sensor terminals.

Terminals

No. 1 — No. 2:

Is the resistance 2 — 3 Ω? Repair the poor

contact of ECM

connector.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 108 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-109

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

O: DTC P0032 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-24, DTC P0032 HO2S HEATER CONTROL CIRCUIT HIGH

(BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 109 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-110

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 5 (+) — Chassis ground (–):

(B136) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

Go to step 2.

2 CHECK GROUND CIRCUIT FOR ECM.

1) Disconnect the connector from ECM.

2) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:

(B134) No. 4 — Chassis ground:

(B134) No. 6 — Chassis ground:

(B137) No. 1 — Chassis ground:

(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Repair the poor

contact of ECM

connector.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 110 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-111

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

P: DTC P0037 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-25, DTC P0037 HO2S HEATER CONTROL CIRCUIT LOW

(BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 111 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-112

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY TO REAR OXY-

GEN SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from rear oxygen

sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between rear oxygen

sensor connector and engine ground.

Connector & terminal

(T6) No. 2 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the power

supply line.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

A/F, oxygen sen-

sor relay and rear

oxygen sensor

connector

• Poor contact of

A/F, oxygen sen-

sor relay connector

• Poor contact of

coupling connector

• Malfunction of A/

F, oxygen sensor

relay

2 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and rear oxygen sensor connector.

Connector & terminal

(B135) No. 6 — (T6) No. 1:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

3 CHECK GROUND CIRCUIT FOR ECM.

Measure the resistance of harness between

ECM connector and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:

(B134) No. 4 — Chassis ground:

(B134) No. 6 — Chassis ground:

(B137) No. 1 — Chassis ground:

(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

4 CHECK REAR OXYGEN SENSOR.

Measure the resistance between rear oxygen

sensor terminals.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 6.4 Ω? Repair the poor

contact of ECM

connector.

Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

15WRX_STI_US_EN.book 112 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-113

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Q: DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-26, DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH

(BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 113 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-114

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and rear

oxygen sensor

connector.

Go to step 2.

2 CHECK GROUND CIRCUIT FOR ECM.

1) Disconnect the connector from ECM.

2) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:

(B134) No. 4 — Chassis ground:

(B134) No. 6 — Chassis ground:

(B137) No. 1 — Chassis ground:

(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Repair the poor

contact of ECM

connector.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 114 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-115

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

R: DTC P0068 MAP/MAF - THROTTLE POSITION CORRELATION

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-27, DTC P0068 MAP/MAF - THROTTLE POSITION COR-

RELATION, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or

disconnection of hose on air

intake system?

Repair the air

intake system.

Go to step 2.

2 CHECK MANIFOLD ABSOLUTE PRESSURE

SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Read the value of «Mani. Absolute Pres-

sure» using the Subaru Select Monitor or a gen-

eral scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

“General Scan Tool Instruction Manual”.

Is the value in «Mani. Absolute

Pressure» 73.3 — 106.6 kPa

(550 — 800 mmHg, 21.65 —

31.50 inHg) when the ignition is

turned ON, and 20.0 — 46.7

kPa (150 — 350 mmHg, 5.91 —

13.78 inHg) during idling?

Go to step 3. Replace the mani-

fold absolute pres-

sure sensor. <Ref.

to FU(STI)-41,

Manifold Absolute

Pressure Sensor.>

3 CHECK THROTTLE OPENING ANGLE.

Using the Subaru Select Monitor or a general

scan tool, read the value in «Throttle Opening

Angle».

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

“General Scan Tool Instruction Manual”.

Is the value in «Throttle Open-

ing Angle» with the throttle fully

closed less than 5%?

Go to step 4. Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

4 CHECK THROTTLE OPENING ANGLE. Is the value in «Throttle Open-

ing Angle» with the throttle fully

open 85% or more?

Replace the mani-

fold absolute pres-

sure sensor. <Ref.

to FU(STI)-41,

Manifold Absolute

Pressure Sensor.>

Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

15WRX_STI_US_EN.book 115 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-116

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

S: DTC P0071 AMBIENT TEMPERATURE SENSOR CIRCUIT "A" RANGE/PER-

FORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-29, DTC P0071 AMBIENT TEMPERATURE SENSOR CIR-

CUIT "A" RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK CURRENT DATA.

1) Turn the ignition switch to ON.

2) Read the value of «Ambient Air Tempera-

ture» using the Subaru Select Monitor or a gen-

eral scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For HVAC System”.

<Ref. to AC(diag)-40, Read Current Data.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

3) Read the change of the value in «Ambient

Air Temperature» while heating and cooling the

ambient sensor using a hair dryer.

CAUTION:

Do not heat the part to the temperature

where you cannot touch it with your bare

hand in order to prevent burning yourself

and protect the part.

Does the value of «Ambient Air

Temperature» change between

heating and cooling?

Repair the poor

contact of ECM

connector.

Replace the ambi-

ent sensor. <Ref.

to AC-72, Ambient

Sensor.>

15WRX_STI_US_EN.book 116 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-117

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

T: DTC P0072 AMBIENT TEMPERATURE SENSOR CIRCUIT "A" LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-31, DTC P0072 AMBIENT TEMPERATURE SENSOR CIR-

CUIT "A" LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

U: DTC P0073 AMBIENT TEMPERATURE SENSOR CIRCUIT "A" HIGH

NOTE:

For the diagnostic procedure, refer to DTC P0072. <Ref. to EN(STI)(diag)-117, DTC P0072 AMBIENT TEM-

PERATURE SENSOR CIRCUIT "A" LOW, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

Step Check Yes No

1 CHECK DTC.

Check for DTC. <Ref. to EN(STI)(diag)-42,

Read Diagnostic Trouble Code (DTC).>

Is DTC P0072 or P0073 dis-

played?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK COMBINATION METER.

Check the combination meter system. <Ref. to

IDI(diag)-2, Basic Diagnostic Procedure.>

Is the combination meter sys-

tem normal?

Repair the poor

contact of ECM

connector.

Repair the combi-

nation meter sys-

tem. <Ref. to

IDI(diag)-2, Basic

Diagnostic Proce-

dure.>

15WRX_STI_US_EN.book 117 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-118

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

V: DTC P0101 MASS OR VOLUME AIR FLOW CIRCUIT RANGE/PERFOR-

MANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-33, DTC P0101 MASS OR VOLUME AIR FLOW CIRCUIT

RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15WRX_STI_US_EN.book 118 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-119

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

W: DTC P0102 MASS OR VOLUME AIR FLOW CIRCUIT LOW INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-35, DTC P0102 MASS OR VOLUME AIR FLOW CIRCUIT

LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83

456

123

B83

J/C

EN-10859

123

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

B550

216

B220

B135B:

B136C:

B30

C31

C11

C22

C10

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

MAIN RELAY

BATTERY

FUSE HOLDER

MASS AIR FLOW &

INTAKE AIR TEMPERATURE

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 119 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-120

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Air Flow Sensor Volt-

age» using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Air Flow Sensor

Voltage» less than 0.2 V?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK POWER SUPPLY OF MASS AIR

FLOW AND INTAKE AIR TEMPERATURE

SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the mass

air flow and intake air temperature sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between mass air flow

and intake air temperature sensor connector

and engine ground.

Connector & terminal

(B3) No. 3 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

main relay connec-

tor and mass air

flow and intake air

temperature sen-

sor connector

• Poor contact of

main relay connec-

tor

3 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and the mass air flow and

intake air temperature sensor connector.

Connector & terminal

(B136) No. 22 — (B3) No. 5:

Is the resistance less than 1 Ω? Go to step 4. Repair the open

circuit of harness

between ECM con-

nector and the

mass air flow and

intake air tempera-

ture sensor con-

nector.

4 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 22 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the ground

short circuit of har-

ness between

ECM connector

and the mass air

flow and intake air

temperature sen-

sor connector.

5 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and mass air

flow and intake air temperature sensor connec-

tor.

Is there poor contact of ECM or

mass air flow and intake air

temperature sensor connector?

Repair the poor

contact of ECM or

mass air flow and

intake air tempera-

ture sensor con-

nector.

Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15WRX_STI_US_EN.book 120 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-121

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

X: DTC P0103 MASS OR VOLUME AIR FLOW CIRCUIT HIGH INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-36, DTC P0103 MASS OR VOLUME AIR FLOW CIRCUIT

HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83

456

123

B83

J/C

EN-10859

123

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

B550

216

B220

B135B:

B136C:

B30

C31

C11

C22

C10

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

MAIN RELAY

BATTERY

FUSE HOLDER

MASS AIR FLOW &

INTAKE AIR TEMPERATURE

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 121 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-122

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Air Flow Sensor Volt-

age» using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Air Flow Sensor

Voltage» 5 V or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the mass

air flow and intake air temperature sensor.

3) Start the engine.

4) Read the value of «Air Flow Sensor Volt-

age» using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Air Flow Sensor

Voltage» 5 V or more?

Repair the short

circuit of harness

to power supply

between ECM con-

nector and the

mass air flow and

intake air tempera-

ture sensor con-

nector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance of harness between

mass air flow and intake air temperature sensor

connector and engine ground.

Connector & terminal

(B3) No. 4 — Engine ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the mass air

flow and intake air

temperature sen-

sor connector

• Poor contact of

ECM connector

4 CHECK FOR POOR CONTACT.

Check for poor contact of mass air flow and

intake air temperature sensor connector.

Is there poor contact of mass

air flow and intake air tempera-

ture sensor connector?

Repair the poor

contact of mass air

flow and intake air

temperature sen-

sor connector.

Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15WRX_STI_US_EN.book 122 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-123

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Y: DTC P0107 MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRESSURE

CIRCUIT LOW INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-37, DTC P0107 MANIFOLD ABSOLUTE PRESSURE/

BAROMETRIC PRESSURE CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B134A:

B137D:

E2B21

E21

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

A29

D20

A19

EN-10860

213

E21

ECM

MANIFOLD ABSOLUTE

PRESSURE SENSOR

15WRX_STI_US_EN.book 123 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-124

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Mani. Absolute Pres-

sure» using the Subaru Select Monitor or a gen-

eral scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mani. Absolute

Pressure» less than 13.3 kPa

(100 mmHg, 3.94 inHg)?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK POWER SUPPLY OF MANIFOLD

ABSOLUTE PRESSURE SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from manifold

absolute pressure sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between manifold

absolute pressure sensor connector and

engine ground.

Connector & terminal

(E21) No. 3 (+) — Engine ground (–):

Is the voltage 4.5 V or more? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and manifold abso-

lute pressure sen-

sor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

MANIFOLD ABSOLUTE PRESSURE SEN-

SOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and manifold absolute pressure

sensor connector.

Connector & terminal

(B137) No. 20 — (E21) No. 1:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and manifold abso-

lute pressure sen-

sor connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

MANIFOLD ABSOLUTE PRESSURE SEN-

SOR CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 20 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair short cir-

cuit to ground in

harness between

ECM connector

and manifold abso-

lute pressure sen-

sor connector.

5 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and manifold

absolute pressure sensor connector.

Is there poor contact of ECM or

manifold absolute pressure

sensor connector?

Repair the poor

contact of ECM or

manifold absolute

pressure sensor

connector.

Replace the mani-

fold absolute pres-

sure sensor. <Ref.

to FU(STI)-41,

Manifold Absolute

Pressure Sensor.>

15WRX_STI_US_EN.book 124 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-125

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Z: DTC P0108 MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRESSURE

CIRCUIT HIGH INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-38, DTC P0108 MANIFOLD ABSOLUTE PRESSURE/

BAROMETRIC PRESSURE CIRCUIT HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B134A:

B137D:

E2B21

E21

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

A29

D20

A19

EN-10860

213

E21

ECM

MANIFOLD ABSOLUTE

PRESSURE SENSOR

15WRX_STI_US_EN.book 125 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-126

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Mani. Absolute Pres-

sure» using the Subaru Select Monitor or a gen-

eral scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mani. Absolute

Pressure» 119.5 kPa (896.5

mmHg, 35.29 inHg) or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

MANIFOLD ABSOLUTE PRESSURE SEN-

SOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from manifold

absolute pressure sensor.

3) Start the engine.

4) Read the value of «Mani. Absolute Pres-

sure» using the Subaru Select Monitor or a gen-

eral scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mani. Absolute

Pressure» 119.5 kPa (896.5

mmHg, 35.29 inHg) or more?

Repair the short

circuit to power in

harness between

ECM connector

and manifold abso-

lute pressure sen-

sor connector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

MANIFOLD ABSOLUTE PRESSURE SEN-

SOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance of harness between

manifold absolute pressure sensor connector

and engine ground.

Connector & terminal

(E21) No. 2 — Engine ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and manifold abso-

lute pressure sen-

sor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

4 CHECK FOR POOR CONTACT.

Check for poor contact of manifold absolute

pressure sensor connector.

Is there poor contact of mani-

fold absolute pressure sensor

connector?

Repair the poor

contact of mani-

fold absolute pres-

sure sensor

connector.

Replace the mani-

fold absolute pres-

sure sensor. <Ref.

to FU(STI)-41,

Manifold Absolute

Pressure Sensor.>

15WRX_STI_US_EN.book 126 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-127

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AA:DTC P0111 INTAKE AIR TEMPERATURE SENSOR RANGE/PERFORMANCE

PROBLEM

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-39, DTC P0111 INTAKE AIR TEMPERATURE SENSOR

RANGE/PERFORMANCE PROBLEM, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK CURRENT DATA.

1) Turn the ignition switch to ON.

2) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

3) Read the change of the value in «Intake Air

Temp.» while heating and cooling the mass air

flow and intake air temperature sensor using a

hair dryer.

CAUTION:

Do not heat the part to the temperature

where you cannot touch it with your bare

hand in order to prevent burning yourself

and protect the part.

Does the value of «Intake Air

Temp.» change between heat-

ing and cooling?

Repair the poor

contact of ECM

connector.

Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15WRX_STI_US_EN.book 127 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-128

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AB:DTC P0112 INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-42, DTC P0112 INTAKE AIR TEMPERATURE SENSOR 1

CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83

456

123

B83

J/C

EN-10859

123

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

B550

216

B220

B135B:

B136C:

B30

C31

C11

C22

C10

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

MAIN RELAY

BATTERY

FUSE HOLDER

MASS AIR FLOW &

INTAKE AIR TEMPERATURE

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 128 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-129

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Intake Air

Temp.» 120°C (248°F) or

more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

the mass air flow and intake air temperature

sensor.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 31 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

Repair the ground

short circuit of har-

ness between

ECM connector

and the mass air

flow and intake air

temperature sen-

sor connector.

15WRX_STI_US_EN.book 129 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-130

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AC:DTC P0113 INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-43, DTC P0113 INTAKE AIR TEMPERATURE SENSOR 1

CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83

456

123

B83

J/C

EN-10859

123

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

B550

216

B220

B135B:

B136C:

B30

C31

C11

C22

C10

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

MAIN RELAY

BATTERY

FUSE HOLDER

MASS AIR FLOW &

INTAKE AIR TEMPERATURE

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 130 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-131

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Intake Air Temp.»

less than –40°C (–40°F)?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and mass air

flow and intake air temperature sensor connec-

tor.

Is there poor contact of ECM or

mass air flow and intake air

temperature sensor connector?

Repair the poor

contact of ECM or

mass air flow and

intake air tempera-

ture sensor con-

nector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

the mass air flow and intake air temperature

sensor.

3) Measure the resistance of harness between

ECM connector and the mass air flow and

intake air temperature sensor connector.

Connector & terminal

(B136) No. 31 — (B3) No. 1:

(B135) No. 30 — (B3) No. 2:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the mass air

flow and intake air

temperature sen-

sor connector

• Poor contact of

joint connector

4 CHECK HARNESS BETWEEN ECM AND

MASS AIR FLOW AND INTAKE AIR TEM-

PERATURE SENSOR CONNECTOR.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 31 (+) — Chassis ground (–):

Is the voltage 5 V or more? Repair the short

circuit of harness

to power supply

between ECM con-

nector and the

mass air flow and

intake air tempera-

ture sensor con-

nector.

Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15WRX_STI_US_EN.book 131 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-132

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AD:DTC P0116 ENGINE COOLANT TEMPERATURE SENSOR 1 CIRCUIT

RANGE/PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-44, DTC P0116 ENGINE COOLANT TEMPERATURE SEN-

SOR 1 CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Hard to start

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK ENGINE COOLANT TEMPERATURE

SENSOR.

1) Disconnect the connectors from the engine

coolant temperature sensor.

2) Measure the resistance between engine

coolant temperature sensor terminals when the

engine coolant is cold and after warmed up.

Terminals

No. 1 — No. 2:

Is the resistance of engine cool-

ant temperature sensor differ-

ent between when engine

coolant is cold and after

warmed up?

Repair the poor

contact of ECM

connector.

Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

15WRX_STI_US_EN.book 132 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-133

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AE:DTC P0117 ENGINE COOLANT TEMPERATURE CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-46, DTC P0117 ENGINE COOLANT TEMPERATURE CIR-

CUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Hard to start

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B134A:

B137D:

E2B21

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

A29

D22

EN-10171

ECM

ENGINE COOLANT

TEMPERATURE

SENSOR

15WRX_STI_US_EN.book 133 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-134

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

150°C (302°F) or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND EN-

GINE COOLANT TEMPERATURE SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

engine coolant temperature sensor.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B137) No. 22 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

Repair the short

circuit to ground in

harness between

ECM connector

and engine coolant

temperature sen-

sor connector.

15WRX_STI_US_EN.book 134 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-135

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AF:DTC P0118 ENGINE COOLANT TEMPERATURE CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-47, DTC P0118 ENGINE COOLANT TEMPERATURE CIR-

CUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Hard to start

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B134A:

B137D:

E2B21

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

A29

D22

EN-10171

ECM

ENGINE COOLANT

TEMPERATURE

SENSOR

15WRX_STI_US_EN.book 135 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-136

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

less than –40°C (–40°F)?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and engine cool-

ant temperature sensor connector.

Is there poor contact of ECM or

engine coolant temperature

sensor connector?

Repair the poor

contact of ECM or

engine coolant

temperature sen-

sor connector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND EN-

GINE COOLANT TEMPERATURE SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

engine coolant temperature sensor.

3) Measure the resistance of harness between

ECM connector and engine coolant tempera-

ture sensor connector.

Connector & terminal

(B134) No. 29 — (E8) No. 1:

(B137) No. 22 — (E8) No. 2:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and engine coolant

temperature sen-

sor connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND EN-

GINE COOLANT TEMPERATURE SENSOR

CONNECTOR.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 22 (+) — Chassis ground (–):

Is the voltage 5 V or more? Repair the short

circuit of harness

to power supply

between ECM con-

nector and engine

coolant tempera-

ture sensor con-

nector.

Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

15WRX_STI_US_EN.book 136 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-137

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AG:DTC P0122 THROTTLE/PEDAL POSITION SENSOR/SWITCH “A” CIRCUIT

LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-48, DTC P0122 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “A” CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 137 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-138

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 19 — Chassis ground:

(B134) No. 18 — Chassis ground:

(B134) No. 18 — (B136) No. 4:

Is the resistance 1 MΩ or

more?

Go to step 2. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 138 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-139

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 6 — Engine ground:

Is the resistance 1 MΩ or

more?

Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

Step Check Yes No

15WRX_STI_US_EN.book 139 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-140

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AH:DTC P0123 THROTTLE/PEDAL POSITION SENSOR/SWITCH “A” CIRCUIT

HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-49, DTC P0123 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “A” CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 140 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-141

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance of harness between

ECM connector and electronic throttle control

connector.

Connector & terminal

(B134) No. 18 — (E57) No. 6:

(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 141 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-142

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 6 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B134) No. 19 — (B134) No. 18:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Step Check Yes No

15WRX_STI_US_EN.book 142 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-143

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AI: DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP

FUEL CONTROL

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-50, DTC P0125 INSUFFICIENT COOLANT TEMPERA-

TURE FOR CLOSED LOOP FUEL CONTROL, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Engine does not return to idle.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK TIRE SIZE. Is the tire size as specified and

the same size as three other

wheels?

Go to step 2. Replace the tire.

2 CHECK ENGINE COOLANT.

Check the following items:

• Amount of engine coolant

• Engine coolant freeze

• Contamination of engine coolant

Is the engine coolant normal? Go to step 3. Fill or replace the

engine coolant.

<Ref. to CO(STI)-

13, Engine Cool-

ant.>

3 CHECK THERMOSTAT. Does the thermostat remain

opened?

Replace the ther-

mostat. <Ref. to

CO(STI)-17, Ther-

mostat.>

Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

15WRX_STI_US_EN.book 143 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-144

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AJ:DTC P0128 COOLANT THERMOSTAT (ENGINE COOLANT TEMPERATURE

BELOW THERMOSTAT REGULATING TEMPERATURE)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-52, DTC P0128 COOLANT THERMOSTAT (ENGINE

COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE), Diagnostic Trouble

Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Thermostat remains open.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK ENGINE COOLANT. Is the engine coolant amount

normal?

Go to step 3. Refill the engine

coolant. <Ref. to

CO(STI)-13,

Engine Coolant.>

3 CHECK RADIATOR FAN.

1) Start the engine.

2) Check the radiator fan operation.

Does the radiator fan continu-

ously rotate for 3 minutes or

more during idling?

Repair radiator fan

circuit. <Ref. to

CO(STI)-23, Radi-

ator Main Fan and

Fan Motor.> <Ref.

to CO(STI)-25,

Radiator Sub Fan

and Fan Motor.>

Replace the ther-

mostat. <Ref. to

CO(STI)-17, Ther-

mostat.>

15WRX_STI_US_EN.book 144 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-145

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AK:DTC P0131 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-56, DTC P0131 O2 SENSOR CIRCUIT LOW VOLTAGE

(BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 145 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-146

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 18 — Chassis ground:

(B136) No. 19 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector.

3 CHECK FOR POOR CONTACT.

Check for poor contact of the front oxygen (A/F)

sensor connector.

Is there poor contact of front

oxygen (A/F) sensor connec-

tor?

Repair the poor

contact of front

oxygen (A/F) sen-

sor connector.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 146 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-147

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AL:DTC P0132 O2 SENSOR CIRCUIT HIGH VOLTAGE (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-57, DTC P0132 O2 SENSOR CIRCUIT HIGH VOLTAGE

(BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 147 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-148

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from front oxy-

gen (A/F) sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 18 (+) — Chassis ground (–):

(B136) No. 19 (+) — Chassis ground (–):

Is the voltage 8 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 148 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-149

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AM:DTC P0134 O2 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 1 SEN-

SOR 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-58, DTC P0134 O2 SENSOR CIRCUIT NO ACTIVITY DE-

TECTED (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 149 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-150

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

3) Measure the resistance of harness between

ECM connector and front oxygen (A/F) sensor

connector.

Connector & terminal

(B136) No. 18 — (B379) No. 3:

(B136) No. 19 — (B379) No. 4:

Is the resistance less than 1 Ω? Go to step 2. Repair the open

circuit of harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and front oxygen

(A/F) sensor connector.

Is there poor contact of ECM or

front oxygen (A/F) sensor con-

nector?

Repair the poor

contact of ECM or

front oxygen (A/F)

sensor connector.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 150 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-151

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AN:DTC P0137 O2 SENSOR CIRCUIT LOW VOLTAGE (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-59, DTC P0137 O2 SENSOR CIRCUIT LOW VOLTAGE

(BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 151 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-152

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

keep the engine speed at 3,000 rpm. (2 minutes

maximum)

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.490 V or more?

Go to step 5. Go to step 2.

2 CHECK REAR OXYGEN SENSOR CONNEC-

TOR AND COUPLING CONNECTOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 (+) — Chassis ground (–):

Is the voltage 0.2 — 0.5 V? Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

5 CHECK EXHAUST SYSTEM.

Check exhaust system parts.

NOTE:

Check the following items.

• Looseness and improper fitting of exhaust

system parts

• Damage (crack, hole etc.) of parts

• Loose part and improper installation between

front oxygen (A/F) sensor and rear oxygen sen-

sor

Is there any fault in exhaust

system?

Repair or replace

faulty parts.

Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

15WRX_STI_US_EN.book 152 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-153

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AO:DTC P0138 O2 SENSOR CIRCUIT HIGH VOLTAGE (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-60, DTC P0138 O2 SENSOR CIRCUIT HIGH VOLTAGE

(BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 153 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-154

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

rapidly reduce the engine speed from 3,000

rpm.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“Current Data Display For Engine”. <Ref. to

EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.250 V or less?

Go to step 5. Go to step 2.

2 CHECK REAR OXYGEN SENSOR CONNEC-

TOR AND COUPLING CONNECTOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 (+) — Chassis ground (–):

Is the voltage 0.2 — 0.5 V? Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

5 CHECK EXHAUST SYSTEM.

Check exhaust system parts.

NOTE:

Check the following items.

• Looseness and improper fitting of exhaust

system parts

• Damage (crack, hole etc.) of parts

• Loose part and improper installation between

front oxygen (A/F) sensor and rear oxygen sen-

sor

Is there any fault in exhaust

system?

Repair or replace

faulty parts.

Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

15WRX_STI_US_EN.book 154 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-155

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AP:DTC P013A O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SEN-

SOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-61, DTC P013A O2 SENSOR SLOW RESPONSE - RICH

TO LEAN (BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 155 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-156

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

Measure the resistance between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and rear oxygen

sensor connector.

3 CHECK REAR OXYGEN SENSOR.

Measure the resistance between rear oxygen

sensor terminals.

Terminals

No. 3 — No. 4

Is the resistance less than 1 Ω? Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 156 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-157

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AQ:DTC P013B O2 SENSOR SLOW RESPONSE - LEAN TO RICH (BANK 1 SEN-

SOR 2)

NOTE:

For the diagnostic procedure, refer to DTC P013A. <Ref. to EN(STI)(diag)-155, DTC P013A O2 SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

AR:DTC P013E O2 SENSOR DELAYED RESPONSE - RICH TO LEAN (BANK 1

SENSOR 2)

NOTE:

For the diagnostic procedure, refer to DTC P013A. <Ref. to EN(STI)(diag)-155, DTC P013A O2 SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

AS:DTC P013F O2 SENSOR DELAYED RESPONSE - LEAN TO RICH (BANK 1

SENSOR 2)

NOTE:

For the diagnostic procedure, refer to DTC P013A. <Ref. to EN(STI)(diag)-155, DTC P013A O2 SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

AT:DTC P0141 O2 SENSOR HEATER CIRCUIT (BANK1 SENSOR2)

NOTE:

For the diagnostic procedure, refer to DTC P0037. <Ref. to EN(STI)(diag)-111, DTC P0037 HO2S HEATER

CONTROL CIRCUIT LOW (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble Code

(DTC).>

15WRX_STI_US_EN.book 157 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-158

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AU:DTC P014C O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SEN-

SOR 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-70, DTC P014C O2 SENSOR SLOW RESPONSE - RICH

TO LEAN (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

AV:DTC P014D O2 SENSOR SLOW RESPONSE - LEAN TO RICH (BANK 1 SEN-

SOR 1)

NOTE:

For the diagnostic procedure, refer to DTC P014C. <Ref. to EN(STI)(diag)-158, DTC P014C O2 SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

AW:DTC P015A O2 SENSOR DELAYED RESPONSE - RICH TO LEAN (BANK 1

SENSOR 1)

NOTE:

For the diagnostic procedure, refer to DTC P014C. <Ref. to EN(STI)(diag)-158, DTC P014C O2 SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

AX:DTC P015B O2 SENSOR DELAYED RESPONSE - LEAN TO RICH (BANK 1

SENSOR 1)

NOTE:

For the diagnostic procedure, refer to DTC P014C. <Ref. to EN(STI)(diag)-158, DTC P014C O2 SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

AY:DTC P0171 SYSTEM TOO LEAN (BANK 1)

NOTE:

For the diagnostic procedure, refer to DTC P0172. <Ref. to EN(STI)(diag)-159, DTC P0172 SYSTEM TOO

RICH (BANK 1), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

Step Check Yes No

1 CHECK EXHAUST SYSTEM.

NOTE:

Check the following items.

• Loose installation of front portion of exhaust

pipe onto cylinder heads

• Loose connection between front exhaust pipe

and front catalytic converter

• Damage of exhaust pipe resulting in a hole

Is there any fault in exhaust

system?

Repair the exhaust

system.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 158 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-159

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AZ:DTC P0172 SYSTEM TOO RICH (BANK 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-79, DTC P0172 SYSTEM TOO RICH (BANK 1), Diagnostic

Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK EXHAUST SYSTEM. Are there holes or loose bolts

on exhaust system?

Repair the exhaust

system.

Go to step 2.

2 CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or

disconnection of hose on air

intake system?

Repair the air

intake system.

Go to step 3.

3 CHECK FUEL PRESSURE.

WARNING:

Place “NO OPEN FLAMES” signs near the

working area.

CAUTION:

Be careful not to spill fuel.

Measure the fuel pressure while disconnecting

pressure regulator vacuum hose from intake

manifold. <Ref. to ME(STI)-25, INSPECTION,

Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

If fuel pressure does not increase, squeeze the

fuel return hose 2 to 3 times, then measure fuel

pressure again.

Is the measured value 284 —

314 kPa (2.9 — 3.2 kg/cm

, 41

— 46 psi)?

Go to step 4. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

4 CHECK FUEL PRESSURE.

After connecting the pressure regulator vacuum

hose, measure fuel pressure. <Ref. to ME(STI)-

25, INSPECTION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

• If fuel pressure does not increase, squeeze

fuel return hose 2 to 3 times, then measure fuel

pressure again.

• If the measured value at this step is out of

specification, check or replace pressure regula-

tor and pressure regulator vacuum hose.

Is the measured value 230 —

260 kPa (2.4 — 2.7 kg/cm

, 33

— 38 psi)?

Go to step 5. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

15WRX_STI_US_EN.book 159 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-160

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

5 CHECK ENGINE COOLANT TEMPERATURE

SENSOR.

1) Start the engine and warm up completely.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

75°C (167°F) or more?

Go to step 6. Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

6 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Read the value of «Mass Air Flow» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mass Air

Flow» 2.0 — 5.0 g/s (0.26 —

0.66 lb/m)?

Go to step 7. Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

7 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Open the front hood.

6) Measure the ambient temperature.

7) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Subtract ambient temperature

from «Intake Air Temp.». Is the

obtained value –10 — 50°C (–18

— 90°F)?

Repair the poor

contact of ECM

connector.

Check the mass air

flow and intake air

temperature sen-

sor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

Step Check Yes No

15WRX_STI_US_EN.book 160 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-161

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BA:DTC P0201 INJECTOR #1

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-80, DTC P0201 INJECTOR #1, Diagnostic Trouble Code

(DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B220

B550

216

B21

B134

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B134

10 11 12 13 14 15

72134

19 20 22

28 29

18 2521 23 24

3231

26 27

33 34

EN-10855

E16

E17

E16

E17

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

FUEL INJECTOR No. 4

FUEL INJECTOR No. 3

FUEL INJECTOR No. 2

FUEL INJECTOR No. 1

BATTERY

FUSE HOLDER

MAIN RELAY

15WRX_STI_US_EN.book 161 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-162

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY TO FUEL INJEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector.

3) Turn the ignition switch to ON.

4) Measure the voltage between fuel injector

connector and the engine ground.

Connector & terminal

DTC P0201; (E5) No. 1 (+) — Engine

ground (–):

DTC P0202; (E16) No. 1 (+) — Engine

ground (–):

DTC P0203; (E6) No. 1 (+) — Engine

ground (–):

DTC P0204; (E17) No. 1 (+) — Engine

ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

main relay and fuel

injector connector

• Poor contact of

main relay connec-

tor

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between fuel injec-

tor connector and engine ground.

Connector & terminal

DTC P0201; (E5) No. 2 — Engine ground:

DTC P0202; (E16) No. 2 — Engine ground:

DTC P0203; (E6) No. 2 — Engine ground:

DTC P0204; (E17) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and fuel injector

connector.

3 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

Measure the resistance of harness between

ECM connector and fuel injector connector.

Connector & terminal

DTC P0201; (B134) No. 10 — (E5) No. 2:

DTC P0202; (B134) No. 11 — (E16) No. 2:

DTC P0203; (B134) No. 12 — (E6) No. 2:

DTC P0204; (B134) No. 13 — (E17) No. 2:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and fuel injector

connector

• Poor contact of

coupling connector

4 CHECK FUEL INJECTOR.

Measure the resistance between fuel injector

terminals on the corresponding cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 5. Replace the fuel

injector. <Ref. to

FU(STI)-43, Fuel

Injector.>

5 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Go to step 6.

15WRX_STI_US_EN.book 162 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-163

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BB:DTC P0202 INJECTOR #2

NOTE:

For the diagnostic procedure, refer to DTC P0201. <Ref. to EN(STI)(diag)-161, DTC P0201 INJECTOR #1,

Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

BC:DTC P0203 INJECTOR #3

NOTE:

For the diagnostic procedure, refer to DTC P0201. <Ref. to EN(STI)(diag)-161, DTC P0201 INJECTOR #1,

Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

BD:DTC P0204 INJECTOR #4

NOTE:

For the diagnostic procedure, refer to DTC P0201. <Ref. to EN(STI)(diag)-161, DTC P0201 INJECTOR #1,

Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

6 CHECK FUEL INJECTOR OPERATION.

1) Connect all connectors.

2) Start the engine.

3) Check if the corresponding fuel injector

emits operating sound.

NOTE:

Use a sound scope to check the operating

sound.

Does the fuel injector emit

operating sound?

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Repair the poor

contact of fuel

injector connector.

Step Check Yes No

15WRX_STI_US_EN.book 163 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-164

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BE:DTC P0222 THROTTLE/PEDAL POSITION SENSOR/SWITCH “B” CIRCUIT

LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-81, DTC P0222 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “B” CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

15WRX_STI_US_EN.book 164 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-165

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 19 — Chassis ground:

(B134) No. 28 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 2. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 165 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-166

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 4 — Engine ground:

Is the resistance 1 MΩ or

more?

Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

Step Check Yes No

15WRX_STI_US_EN.book 166 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-167

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BF:DTC P0223 THROTTLE/PEDAL POSITION SENSOR/SWITCH “B” CIRCUIT

HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-82, DTC P0223 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “B” CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 167 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-168

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance of harness between

ECM connector and electronic throttle control

connector.

Connector & terminal

(B134) No. 28 — (E57) No. 4:

(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 168 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-169

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 4 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B134) No. 19 — (B134) No. 28:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Step Check Yes No

15WRX_STI_US_EN.book 169 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-170

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BG:DTC P0230 FUEL PUMP PRIMARY CIRCUIT

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-83, DTC P0230 FUEL PUMP PRIMARY CIRCUIT, Diagnos-

tic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

R58

56789

R122

B135B

B136C

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

B97

1234 56789

10 11 12 13 14 15 16 17 18 19 20

EN-10862

R58

B97

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

R122

C33

B10

ECM

FUEL PUMP CU

BATTERY

FUEL PUMP RELAY

M/B No. 11

FUEL PUMP

15WRX_STI_US_EN.book 170 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-171

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY CIRCUIT TO FUEL

PUMP CONTROL UNIT.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel pump

control unit.

3) Turn the ignition switch to ON.

4) Measure the voltage between fuel pump

control unit connector and chassis ground.

Connector & terminal

(R122) No. 10 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the power

supply circuit.

NOTE:

In this case, repair

the following item:

• Open circuit or

short circuit to

ground in harness

between fuel pump

relay connector

and fuel pump con-

trol unit connector

• Poor contact of

fuel pump relay

connector

• Poor contact of

coupling connector

2 CHECK GROUND CIRCUIT OF FUEL PUMP

CONTROL UNIT.

1) Turn the ignition switch to OFF.

2) Measure the resistance of harness between

fuel pump control unit connector and chassis

ground.

Connector & terminal

(R122) No. 5 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 3. Repair the open

circuit in harness

between fuel pump

control unit con-

nector and chassis

ground.

3 CHECK HARNESS BETWEEN FUEL PUMP

CONTROL UNIT AND FUEL PUMP CONNEC-

TOR.

1) Disconnect the connector from fuel pump.

2) Measure the resistance of harness between

fuel pump control unit and fuel pump connector.

Connector & terminal

(R122) No. 7 — (R58) No. 5:

(R122) No. 6 — (R58) No. 6:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

fuel pump control

unit connector and

fuel pump connec-

tor

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN FUEL PUMP

CONTROL UNIT AND FUEL PUMP CONNEC-

TOR.

Measure the resistance between fuel pump

control unit connector and chassis ground.

Connector & terminal

(R122) No. 7 — Chassis ground:

(R122) No. 6 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

fuel pump control

unit connector and

fuel pump connec-

tor.

5 CHECK HARNESS BETWEEN ECM AND

FUEL PUMP CONTROL UNIT CONNECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between

ECM connector and fuel pump control unit con-

nector.

Connector & terminal

(B135) No. 10 — (R122) No. 9:

(B136) No. 33 — (R122) No. 8:

Is the resistance less than 1 Ω? Go to step 6. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and fuel pump con-

trol unit connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 171 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-172

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK HARNESS BETWEEN ECM AND

FUEL PUMP CONTROL UNIT CONNECTOR.

Measure the resistance between fuel pump

control unit connector and chassis ground.

Connector & terminal

(R122) No. 9 — Chassis ground:

(R122) No. 8 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 7. Repair the short

circuit to ground in

harness between

ECM connector

and fuel pump con-

trol unit connector.

7 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and fuel pump

control unit connector.

Is there poor contact of ECM or

fuel pump control unit connec-

tor?

Repair the poor

contact of ECM or

fuel pump control

unit connector.

Go to step 8.

8 CHECK EXPERIENCE OF RUNNING OUT OF

FUEL.

Has the vehicle experienced

running out of fuel?

Finish the diagno-

sis.

NOTE:

DTC may be re-

corded as a result

of fuel pump idling

while running out

of fuel.

Replace the fuel

pump control unit.

<Ref. to FU(STI)-

63, Fuel Pump

Control Unit.>

Step Check Yes No

15WRX_STI_US_EN.book 172 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-173

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BH:DTC P0244 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A”

RANGE/PERFORMANCE

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-84, DTC P0244 TURBO/SUPER CHARGER WASTEGATE

SOLENOID “A” RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK WASTEGATE ACTUATOR PIPING

AND WASTEGATE CONTROL SOLENOID

VALVE PIPING.

Are there any damage or dis-

connection of hose in waste-

gate actuator piping or

wastegate control solenoid

valve piping?

Connect the

wastegate actuator

pipe or wastegate

control solenoid

valve pipe properly.

If defective,

replace the hose.

Replace the waste-

gate control sole-

noid valve. <Ref. to

FU(STI)-50,

Wastegate Control

Solenoid Valve.>

15WRX_STI_US_EN.book 173 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-174

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BI: DTC P0245 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A” LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-85, DTC P0245 TURBO/SUPER CHARGER WASTEGATE

SOLENOID “A” LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 33 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 2. Go to step 3.

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

E2B21

EN-10863

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

B134

E64

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

WASTEGATE CONTROL

SOLENOID VALVE

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 174 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-175

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary open or

short circuit of har-

ness or temporary

poor contact of

connector may be

the cause.

3 CHECK POWER SUPPLY TO WASTEGATE

CONTROL SOLENOID VALVE.

Measure the voltage between wastegate con-

trol solenoid valve connector and engine

ground.

Connector & terminal

(E64) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 4. Repair the power

supply circuit.

4 CHECK HARNESS BETWEEN ECM AND

WASTEGATE CONTROL SOLENOID VALVE

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

wastegate control solenoid valve.

3) Measure the resistance between wastegate

control solenoid valve connector and engine

ground.

Connector & terminal

(E64) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair ground

short circuit of har-

ness between

ECM connector

and wastegate

control solenoid

valve connector.

5 CHECK HARNESS BETWEEN ECM AND

WASTEGATE CONTROL SOLENOID VALVE

CONNECTOR.

Measure the resistance of harness between

ECM connector and wastegate control solenoid

valve connector.

Connector & terminal

(B134) No. 33 — (E64) No. 2:

Is the resistance less than 1 Ω? Go to step 6. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and wastegate

control solenoid

valve connector

• Poor contact of

coupling connector

6 CHECK WASTEGATE CONTROL SOLE-

NOID VALVE.

1) Remove the wastegate control solenoid

valve.

2) Measure the resistance between wastegate

control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 10 — 100 Ω? Repair poor con-

tact of wastegate

control solenoid

valve connector.

Replace the waste-

gate control sole-

noid valve. <Ref. to

FU(STI)-50,

Wastegate Control

Solenoid Valve.>

Step Check Yes No

15WRX_STI_US_EN.book 175 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-176

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BJ:DTC P0246 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A” HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-86, DTC P0246 TURBO/SUPER CHARGER WASTEGATE

SOLENOID “A” HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

WASTEGATE CONTROL SOLENOID VALVE

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

wastegate control solenoid valve.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 33 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair short cir-

cuit to power in

harness between

ECM connector

and wastegate

control solenoid

valve connector.

Go to step 2.

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

E2B21

EN-10863

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

B134

E64

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

WASTEGATE CONTROL

SOLENOID VALVE

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 176 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-177

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK WASTEGATE CONTROL SOLE-

NOID VALVE.

1) Turn the ignition switch to OFF.

2) Measure the resistance between wastegate

control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω? Replace the waste-

gate control sole-

noid valve. <Ref. to

FU(STI)-50,

Wastegate Control

Solenoid Valve.>

Repair the poor

contact of ECM

connector.

Step Check Yes No

15WRX_STI_US_EN.book 177 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-178

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BK:DTC P0300 RANDOM/MULTIPLE CYLINDER MISFIRE DETECTED

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• Immediately at fault recognition (A misfire which could damage catalyst occurs.)

• GENERAL DESCRIPTION <Ref. to GD(STI)-86, DTC P0300 RANDOM/MULTIPLE CYLINDER MISFIRE

DETECTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

• Rough driving

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 178 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-179

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground on all cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 6. Go to step 2.

B220

B550

216

B21

B134

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B134

10 11 12 13 14 15

72134

19 20 22

28 29

18 2521 23 24

3231

26 27

33 34

EN-10855

E16

E17

E16

E17

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

FUEL INJECTOR No. 4

FUEL INJECTOR No. 3

FUEL INJECTOR No. 2

FUEL INJECTOR No. 1

BATTERY

FUSE HOLDER

MAIN RELAY

15WRX_STI_US_EN.book 179 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-180

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from all fuel injec-

tors.

3) Measure the resistance between all fuel

injector connectors and engine ground.

Connector & terminal

#1 (E5) No. 2 — Engine ground:

#2 (E16) No. 2 — Engine ground:

#3 (E6) No. 2 — Engine ground:

#4 (E17) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and fuel injector

connector.

3 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

Measure the resistance of harness between

ECM connector and fuel injector connector on

all cylinders.

Connector & terminal

#1 (B134) No. 10 — (E5) No. 2:

#2 (B134) No. 11 — (E16) No. 2:

#3 (B134) No. 12 — (E6) No. 2:

#4 (B134) No. 13 — (E17) No. 2:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and fuel injector

connector

• Poor contact of

coupling connector

4 CHECK FUEL INJECTOR.

Measure the resistance between all fuel injector

terminals.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 5. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

5 CHECK POWER SUPPLY LINE.

1) Turn the ignition switch to ON.

2) Measure the voltage between all fuel injec-

tor connectors and the engine ground.

Connector & terminal

#1 (E5) No. 1 (+) — Engine ground (–):

#2 (E16) No. 1 (+) — Engine ground (–):

#3 (E6) No. 1 (+) — Engine ground (–):

#4 (E17) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Repair the poor

contact of all con-

nectors in fuel

injector circuit.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

the main relay con-

nector and fuel in-

jector connector on

faulty cylinders

• Poor contact of

coupling connector

• Poor contact of

main relay connec-

tor

6 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from all fuel injec-

tors.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground on all cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and fuel injector

connectors.

Go to step 7.

Step Check Yes No

15WRX_STI_US_EN.book 180 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-181

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

7 CHECK FUEL INJECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between all fuel

injector terminals.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 8. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

8 CHECK INSTALLATION OF CAMSHAFT PO-

SITION SENSOR/CRANKSHAFT POSITION

SENSOR.

Is the camshaft position sensor

or crankshaft position sensor

loosely installed?

Tighten the cam-

shaft position sen-

sor or crankshaft

position sensor.

<Ref. to FU(STI)-

35, Camshaft Posi-

tion Sensor.> <Ref.

to FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

Go to step 9.

9 CHECK CRANK SPROCKET.

Remove the timing belt cover.

Is the crank sprocket rusted or

does it have broken teeth?

Replace the crank

sprocket. <Ref. to

ME(STI)-61, Crank

Sprocket.>

Go to step 10.

10 CHECK INSTALLATION CONDITION OF

TIMING BELT.

Turn the crankshaft, and align alignment mark

on crank sprocket with alignment mark on cylin-

der block.

ST 499987500 CRANKSHAFT

SOCKET

Is the timing belt dislocated

from its proper position?

Repair the installa-

tion condition of

timing belt. <Ref. to

ME(STI)-51, Tim-

ing Belt.>

Go to step 11.

11 CHECK FUEL LEVEL. Is the fuel meter indication

higher than the “Lower” level?

Go to step 12. Refill the fuel so

that the fuel meter

indication is higher

than the “Lower”

level, and proceed

to the next step. Go

to step 12.

12 CHECK STATUS OF MALFUNCTION INDI-

CATOR LIGHT.

1) Clear the memory using the Subaru Select

Monitor or general scan tool. <Ref. to

EN(STI)(diag)-59, Clear Memory Mode.>

2) Start the engine, and drive the vehicle 10

minutes or more.

Does the malfunction indicator

light illuminate or blink?

Go to step 14. Go to step 13.

13 CHECK CAUSE OF MISFIRE. Was the cause of misfire identi-

fied when the engine is run-

ning?

Finish diagnostics

operation, if the

engine has no

abnormality.

Repair the poor

contact of connec-

tor.

NOTE:

In this case, repair

the following item:

• Poor contact of

ignition coil con-

nector

• Poor contact of

fuel injector con-

nector on faulty

cylinders

• Poor contact of

ECM connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 181 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-182

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BL:DTC P0301 CYLINDER 1 MISFIRE DETECTED

NOTE:

For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(STI)(diag)-183, DTC P0304 CYLINDER 4

MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

BM:DTC P0302 CYLINDER 2 MISFIRE DETECTED

NOTE:

For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(STI)(diag)-183, DTC P0304 CYLINDER 4

MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

BN:DTC P0303 CYLINDER 3 MISFIRE DETECTED

NOTE:

For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(STI)(diag)-183, DTC P0304 CYLINDER 4

MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

14 CHECK AIR INTAKE SYSTEM. Is there any fault in air intake

system?

Repair the air

intake system.

NOTE:

Check the follow-

ing items.

• Are there air

leaks or air suction

caused by loose or

dislocated nuts

and bolts?

• Are there cracks

or any disconnec-

tion of hoses?

Go to step 15.

15 CHECK ALL CYLINDERS. Is there a fault in any cylinder? Repair or replace

the faulty part of

the faulty cylinder.

NOTE:

Check the follow-

ing items.

• Spark plug

• Fuel injector

• Ignition coil

• Compression ra-

tio

• Skipping timing

belt teeth

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

Step Check Yes No

15WRX_STI_US_EN.book 182 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-183

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BO:DTC P0304 CYLINDER 4 MISFIRE DETECTED

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• Immediately at fault recognition (A misfire which could damage catalyst occurs.)

• GENERAL DESCRIPTION <Ref. to GD(STI)-94, DTC P0304 CYLINDER 4 MISFIRE DETECTED, Diag-

nostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

• Rough driving

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 183 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-184

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 6. Go to step 2.

B220

B550

216

B21

B134

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B134

10 11 12 13 14 15

72134

19 20 22

28 29

18 2521 23 24

3231

26 27

33 34

EN-10855

E16

E17

E16

E17

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

FUEL INJECTOR No. 4

FUEL INJECTOR No. 3

FUEL INJECTOR No. 2

FUEL INJECTOR No. 1

BATTERY

FUSE HOLDER

MAIN RELAY

15WRX_STI_US_EN.book 184 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-185

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector

on faulty cylinders.

3) Measure the resistance between fuel injec-

tor connector and engine ground on faulty cylin-

ders.

Connector & terminal

#1 (E5) No. 2 — Engine ground:

#2 (E16) No. 2 — Engine ground:

#3 (E6) No. 2 — Engine ground:

#4 (E17) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and fuel injector

connector.

3 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

Measure the resistance of harness between

ECM connector and fuel injector connector on

faulty cylinders.

Connector & terminal

#1 (B134) No. 10 — (E5) No. 2:

#2 (B134) No. 11 — (E16) No. 2:

#3 (B134) No. 12 — (E6) No. 2:

#4 (B134) No. 13 — (E17) No. 2:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and fuel injector

connector

• Poor contact of

coupling connector

4 CHECK FUEL INJECTOR.

Measure the resistance between fuel injector

terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 5. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

5 CHECK POWER SUPPLY LINE.

1) Turn the ignition switch to ON.

2) Measure the voltage between fuel injector

connector of faulty cylinders and engine

ground.

Connector & terminal

#1 (E5) No. 1 (+) — Engine ground (–):

#2 (E16) No. 1 (+) — Engine ground (–):

#3 (E6) No. 1 (+) — Engine ground (–):

#4 (E17) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Repair the poor

contact of all con-

nectors in fuel

injector circuit.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

the main relay con-

nector and fuel in-

jector connector on

faulty cylinders

• Poor contact of

coupling connector

• Poor contact of

main relay connec-

tor

6 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector

on faulty cylinders.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and fuel injector

connectors.

Go to step 7.

Step Check Yes No

15WRX_STI_US_EN.book 185 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-186

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

7 CHECK FUEL INJECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between fuel injec-

tor terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 8. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

8 CHECK INSTALLATION OF CAMSHAFT PO-

SITION SENSOR/CRANKSHAFT POSITION

SENSOR.

Is the camshaft position sensor

or crankshaft position sensor

loosely installed?

Tighten the cam-

shaft position sen-

sor or crankshaft

position sensor.

<Ref. to FU(STI)-

35, Camshaft Posi-

tion Sensor.> <Ref.

to FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

Go to step 9.

9 CHECK CRANK SPROCKET.

Remove the timing belt cover.

Is the crank sprocket rusted or

does it have broken teeth?

Replace the crank

sprocket. <Ref. to

ME(STI)-61, Crank

Sprocket.>

Go to step 10.

10 CHECK INSTALLATION CONDITION OF

TIMING BELT.

Turn the crankshaft, and align alignment mark

on crank sprocket with alignment mark on cylin-

der block.

ST 499987500 CRANKSHAFT

SOCKET

Is the timing belt dislocated

from its proper position?

Repair the installa-

tion condition of

timing belt. <Ref. to

ME(STI)-51, Tim-

ing Belt.>

Go to step 11.

11 CHECK FUEL LEVEL. Is the fuel meter indication

higher than the “Lower” level?

Go to step 12. Refill the fuel so

that the fuel meter

indication is higher

than the “Lower”

level, and proceed

to the next step. Go

to step 12.

12 CHECK STATUS OF MALFUNCTION INDI-

CATOR LIGHT.

1) Clear the memory using the Subaru Select

Monitor or general scan tool. <Ref. to

EN(STI)(diag)-59, Clear Memory Mode.>

2) Start the engine, and drive the vehicle 10

minutes or more.

Does the malfunction indicator

light illuminate or blink?

Go to step 14. Go to step 13.

13 CHECK CAUSE OF MISFIRE. Was the cause of misfire identi-

fied when the engine is run-

ning?

Finish diagnostics

operation, if the

engine has no

abnormality.

Repair the poor

contact of connec-

tor.

NOTE:

In this case, repair

the following item:

• Poor contact of

ignition coil con-

nector

• Poor contact of

fuel injector con-

nector on faulty

cylinders

• Poor contact of

ECM connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 186 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-187

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

14 CHECK AIR INTAKE SYSTEM. Is there any fault in air intake

system?

Repair the air

intake system.

NOTE:

Check the follow-

ing items.

• Are there air

leaks or air suction

caused by loose or

dislocated nuts

and bolts?

• Are there cracks

or any disconnec-

tion of hoses?

Go to step 15.

15 CHECK MISFIRE SYMPTOM.

1) Turn the ignition switch to ON.

2) Check for DTC. <Ref. to EN(STI)(diag)-42,

Read Diagnostic Trouble Code (DTC).>

Does the Subaru Select Moni-

tor or general scan tool indicate

only one DTC?

Go to step 18. Go to step 16.

16 CHECK DTC. Is DTC P0301 and P0303 dis-

played on the Subaru Select

Monitor or general scan tool?

Go to step 19. Go to step 17.

17 CHECK DTC. Is DTC P0302 and P0304 dis-

played on the Subaru Select

Monitor or general scan tool?

Go to step 20. Go to step 21.

18 ONLY ONE CYLINDER. Is there any fault in the cylin-

der?

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

19 GROUP OF #1 AND #3 CYLINDERS. Are there any faults in #1 and

#3 cylinders?

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

• Skipping timing

belt teeth

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

20 GROUP OF #2 AND #4 CYLINDERS. Are there any faults in #2 and

#4 cylinders?

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

• Skipping timing

belt teeth

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

Step Check Yes No

15WRX_STI_US_EN.book 187 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-188

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

21 CYLINDER AT RANDOM. Is the engine idle rough? Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

Step Check Yes No

15WRX_STI_US_EN.book 188 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-189

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BP:DTC P0327 KNOCK SENSOR 1 CIRCUIT LOW (BANK 1 OR SINGLE SEN-

SOR)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-95, DTC P0327 KNOCK SENSOR 1 CIRCUIT LOW (BANK

1 OR SINGLE SENSOR), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Poor driving performance

• Knocking occurs

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

KNOCK SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B137) No. 2 — (B134) No. 29:

Is the resistance less than 500

kΩ?

Go to step 2. Go to step 3.

B134A:

B137D:

E2B21

E14

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

A29

EN-10864

E14

ECM

KNOCK SENSOR

15WRX_STI_US_EN.book 189 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-190

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK KNOCK SENSOR.

1) Disconnect the connector from the knock

sensor.

2) Measure the resistance between knock

sensor connectors.

Terminals

No. 1 — No. 2:

Is the resistance less than 500

kΩ?

Replace the knock

sensor. <Ref. to

FU(STI)-38, Knock

Sensor.>

Repair the short

circuit to ground in

harness between

ECM connector

and knock sensor

connector.

NOTE:

The harness be-

tween both con-

nectors are

shielded. Remove

the shield and re-

pair the short cir-

cuit of harness.

3 CHECK INPUT SIGNAL OF ECM.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 2 (+) — Chassis ground (–):

Is the voltage 2 V or more? Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Repair the short

circuit to ground in

harness between

ECM connector

and knock sensor

connector.

NOTE:

The harness be-

tween both con-

nectors are

shielded. Remove

the shield and re-

pair the short cir-

cuit of harness.

Step Check Yes No

15WRX_STI_US_EN.book 190 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-191

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BQ:DTC P0328 KNOCK SENSOR 1 CIRCUIT HIGH (BANK 1 OR SINGLE SEN-

SOR)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-96, DTC P0328 KNOCK SENSOR 1 CIRCUIT HIGH (BANK

1 OR SINGLE SENSOR), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Poor driving performance

• Knocking occurs

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

KNOCK SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B137) No. 2 — (B134) No. 29:

Is the resistance 600 kΩ or

more?

Go to step 2. Repair the poor

contact of ECM

connector.

B134A:

B137D:

E2B21

E14

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

A29

EN-10864

E14

ECM

KNOCK SENSOR

15WRX_STI_US_EN.book 191 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-192

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK KNOCK SENSOR.

1) Disconnect the connector from the knock

sensor.

2) Measure the resistance between knock

sensor terminals.

Terminals

No. 1 — No. 2:

Is the resistance 600 kΩ or

more?

Replace the knock

sensor. <Ref. to

FU(STI)-38, Knock

Sensor.>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and knock sensor

connector

• Poor contact of

knock sensor con-

nector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 192 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-193

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BR:DTC P0335 CRANKSHAFT POSITION SENSOR “A” CIRCUIT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-97, DTC P0335 CRANKSHAFT POSITION SENSOR “A”

CIRCUIT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK CONDITION OF CRANKSHAFT PO-

SITION SENSOR.

Is the crankshaft position sen-

sor installation bolt tightened

securely?

Go to step 2. Tighten the crank-

shaft position sen-

sor installation bolt

securely. <Ref. to

FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

E10

B137

E2B21

E10

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-09557

ECM

CRANKSHAFT

POSITION SENSOR

15WRX_STI_US_EN.book 193 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-194

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK CRANKSHAFT POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Remove the crankshaft position sensor.

3) Measure the resistance between terminals

of crankshaft position sensor.

Terminals

No. 1 — No. 2:

Is the resistance between 1 and

4 kΩ?

Go to step 3. Replace the crank-

shaft position sen-

sor. <Ref. to

FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

3 CHECK HARNESS BETWEEN ECM AND

CRANKSHAFT POSITION SENSOR CON-

NECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between

ECM connector and crankshaft position sensor

connector.

Connector & terminal

(B137) No. 17 — (E10) No. 1:

(B137) No. 25 — (E10) No. 2:

Is the resistance less than 1 Ω? Repair the poor

contact of ECM

and crankshaft

position sensor

connector.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and crankshaft po-

sition sensor con-

nector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 194 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-195

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BS:DTC P0336 CRANKSHAFT POSITION SENSOR “A” CIRCUIT RANGE/PER-

FORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-99, DTC P0336 CRANKSHAFT POSITION SENSOR “A”

CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK CONDITION OF CRANKSHAFT PO-

SITION SENSOR.

Turn the ignition switch to OFF.

Is the crankshaft position sen-

sor installation bolt tightened

securely?

Go to step 2. Tighten the crank-

shaft position sen-

sor installation bolt

securely. <Ref. to

FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

2 CHECK CRANK SPROCKET.

Remove the timing belt cover.

Are crank sprocket teeth

cracked or damaged?

Replace the crank

sprocket. <Ref. to

ME(STI)-61, Crank

Sprocket.>

Go to step 3.

3 CHECK INSTALLATION CONDITION OF

TIMING BELT.

Turn the crankshaft, and align alignment mark

on crank sprocket with alignment mark on cylin-

der block.

ST 499987500 CRANKSHAFT

SOCKET

Is the timing belt dislocated

from its proper position?

Repair the installa-

tion condition of

timing belt. <Ref. to

ME(STI)-51, Tim-

ing Belt.>

Replace the crank-

shaft position sen-

sor. <Ref. to

FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

15WRX_STI_US_EN.book 195 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-196

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BT:DTC P0340 CAMSHAFT POSITION SENSOR “A” CIRCUIT (BANK 1 OR SIN-

GLE SENSOR)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-101, DTC P0340 CAMSHAFT POSITION SENSOR “A” CIR-

CUIT (BANK 1 OR SINGLE SENSOR), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

E36E35

EN-10865

B550

21611

B220

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

B137

E35

E36

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

INTAKE CAMSHAFT

POSITION SENSOR RH

INTAKE CAMSHAFT

POSITION SENSOR LH

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 196 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-197

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY OF CAMSHAFT

POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from camshaft

position sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between camshaft

position sensor connector and engine ground.

Connector & terminal

(E36) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit or

short circuit to

ground in harness

between main re-

lay connector and

camshaft position

sensor connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and camshaft position sensor connector.

Connector & terminal

(B137) No. 24 — (E36) No. 2:

(B137) No. 30 — (E36) No. 3:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the resistance between camshaft

position sensor connector and engine ground.

Connector & terminal

(E36) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair short cir-

cuit to ground in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector.

4 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the voltage between camshaft posi-

tion sensor connector and engine ground.

Connector & terminal

(E36) No. 2 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and cam-

shaft position

sensor connector.

Go to step 5.

5 CHECK CONDITION OF CAMSHAFT POSI-

TION SENSOR.

Is the camshaft position sensor

installation bolt tightened

securely?

Go to step 6. Tighten the cam-

shaft position sen-

sor installation bolt

securely. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

6 CHECK CAMSHAFT POSITION SENSOR.

Check the waveform of the camshaft position

sensor. <Ref. to EN(STI)(diag)-19, Engine Con-

trol Module (ECM) I/O Signal.>

Is there any abnormality in

waveform?

Replace the cam-

shaft position sen-

sor. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

Repair the follow-

ing item.

• Poor contact of

ECM connector

• Poor contact of

camshaft position

sensor connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 197 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-198

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BU:DTC P0341 CAMSHAFT POSITION SENSOR "A" CIRCUIT RANGE/PERFOR-

MANCE (BANK 1 OR SINGLE SENSOR)

NOTE:

For the diagnostic procedure, refer to DTC P0340. <Ref. to EN(STI)(diag)-196, DTC P0340 CAMSHAFT PO-

SITION SENSOR “A” CIRCUIT (BANK 1 OR SINGLE SENSOR), Diagnostic Procedure with Diagnostic

Trouble Code (DTC).>

15WRX_STI_US_EN.book 198 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-199

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BV:DTC P0345 CAMSHAFT POSITION SENSOR “A” CIRCUIT (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-104, DTC P0345 CAMSHAFT POSITION SENSOR “A” CIR-

CUIT (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

E36E35

EN-10865

B550

21611

B220

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

B137

E35

E36

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

INTAKE CAMSHAFT

POSITION SENSOR RH

INTAKE CAMSHAFT

POSITION SENSOR LH

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 199 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-200

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY OF CAMSHAFT

POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from camshaft

position sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between camshaft

position sensor connector and engine ground.

Connector & terminal

(E35) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit or

short circuit to

ground in harness

between main re-

lay connector and

camshaft position

sensor connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and camshaft position sensor connector.

Connector & terminal

(B137) No. 16 — (E35) No. 2:

(B137) No. 30 — (E35) No. 3:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the resistance between camshaft

position sensor connector and engine ground.

Connector & terminal

(E35) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair short cir-

cuit to ground in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector.

4 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the voltage between camshaft posi-

tion sensor connector and engine ground.

Connector & terminal

(E35) No. 2 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and cam-

shaft position

sensor connector.

Go to step 5.

5 CHECK CONDITION OF CAMSHAFT POSI-

TION SENSOR.

Is the camshaft position sensor

installation bolt tightened

securely?

Go to step 6. Tighten the cam-

shaft position sen-

sor installation bolt

securely. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

6 CHECK CAMSHAFT POSITION SENSOR.

Check the waveform of the camshaft position

sensor. <Ref. to EN(STI)(diag)-19, Engine Con-

trol Module (ECM) I/O Signal.>

Is there any abnormality in

waveform?

Replace the cam-

shaft position sen-

sor. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

Repair the follow-

ing item.

• Poor contact of

ECM connector

• Poor contact of

camshaft position

sensor connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 200 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-201

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BW:DTC P0346 CAMSHAFT POSITION SENSOR "A" CIRCUIT RANGE/PER-

FORMANCE (BANK 2)

NOTE:

For the diagnostic procedure, refer to DTC P0345. <Ref. to EN(STI)(diag)-199, DTC P0345 CAMSHAFT PO-

SITION SENSOR “A” CIRCUIT (BANK 2), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

15WRX_STI_US_EN.book 201 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-202

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BX:DTC P0351 IGNITION COIL A PRIMARY/SECONDARY CIRCUIT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-105, DTC P0351 IGNITION COIL A PRIMARY/SECOND-

ARY CIRCUIT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B72

7856

3412

E32E31

E34E33

123

B72

B550

1024

B225

36 37

E2B21

E31

B134

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B134

10 11 12 13 14 15

72134

19 20 22

28 29

18 2521 23 24

3231

26 27

33 34

EN-10854

E32

E33

E34

101

242322 272625212019

432

698

11 12

B550

SBF-6

ECM

BATTERY

IGNITION COIL No. 4

IGNITION COIL No. 3

IGNITION COIL No. 2

IGNITION COIL No. 1

IG RELAY 1

(PUSH BUTTON

START)

FUSE

HOLDER

F/B No. 12

IGNITION SWITCH

MAIN SBF

: WITHOUT PUSH BUTTON START

: WITH PUSH BUTTON START

15WRX_STI_US_EN.book 202 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-203

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK IGNITION COIL POWER SUPPLY

CIRCUIT.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ignition coil.

3) Turn the ignition switch to ON.

4) Measure the voltage between ignition coil

connector and engine ground.

Connector & terminal

DTC P0351; (E31) No. 3 (+) — Engine

ground (–):

DTC P0352; (E32) No. 3 (+) — Engine

ground (–):

DTC P0353; (E33) No. 3 (+) — Engine

ground (–):

DTC P0354; (E34) No. 3 (+) — Engine

ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit or

short circuit to

ground in harness

of power supply

circuit

• Blown out of fuse

• Poor contact of

coupling connector

2 CHECK HARNESS OF IGNITION COIL

GROUND CIRCUIT.

1) Turn the ignition switch to OFF.

2) Measure the resistance of harness between

ignition coil connector and engine ground.

Connector & terminal

DTC P0351; (E31) No. 2 — Engine ground:

DTC P0352; (E32) No. 2 — Engine ground:

DTC P0353; (E33) No. 2 — Engine ground:

DTC P0354; (E34) No. 2 — Engine ground:

Is the resistance less than 5 Ω? Go to step 3. Repair the open

circuit in harness

between ignition

coil connector and

engine grounding

terminal.

3 CHECK HARNESS BETWEEN ECM AND IG-

NITION COIL CONNECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance between ignition

coil connector and engine ground.

Connector & terminal

DTC P0351; (E31) No. 1 — Engine ground:

DTC P0352; (E32) No. 1 — Engine ground:

DTC P0353; (E33) No. 1 — Engine ground:

DTC P0354; (E34) No. 1 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair the ground

short circuit of har-

ness between

ECM connector

and ignition coil

connector.

4 CHECK HARNESS BETWEEN ECM AND IG-

NITION COIL CONNECTOR.

Measure the resistance of harness between

ECM connector and ignition coil connector.

Connector & terminal

DTC P0351; (B134) No. 21 — (E31) No. 1:

DTC P0352; (B134) No. 22 — (E32) No. 1:

DTC P0353; (B134) No. 31 — (E33) No. 1:

DTC P0354; (B134) No. 32 — (E34) No. 1:

Is the resistance less than 1 Ω? Go to step 5. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and the ignition coil

connector

• Poor contact of

coupling connector

5 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Go to step

6 CHECK SPARK PLUG CONDITION.

1) Remove the spark plug of the correspond-

ing cylinder. <Ref. to IG(STI)-4, REMOVAL,

Spark Plug.>

2) Check the spark plug condition. <Ref. to

IG(STI)-5, INSPECTION, Spark Plug.>

Is the spark plug condition nor-

mal?

Replace the igni-

tion coil. <Ref. to

IG(STI)-7, Ignition

Coil.>

Replace the spark

plug. <Ref. to

IG(STI)-4, Spark

Plug.>

15WRX_STI_US_EN.book 203 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-204

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BY:DTC P0352 IGNITION COIL B PRIMARY/SECONDARY CIRCUIT

NOTE:

For the diagnostic procedure, refer to DTC P0351. <Ref. to EN(STI)(diag)-202, DTC P0351 IGNITION COIL

A PRIMARY/SECONDARY CIRCUIT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

BZ:DTC P0353 IGNITION COIL C PRIMARY/SECONDARY CIRCUIT

NOTE:

For the diagnostic procedure, refer to DTC P0351. <Ref. to EN(STI)(diag)-202, DTC P0351 IGNITION COIL

A PRIMARY/SECONDARY CIRCUIT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

CA:DTC P0354 IGNITION COIL D PRIMARY/SECONDARY CIRCUIT

NOTE:

For the diagnostic procedure, refer to DTC P0351. <Ref. to EN(STI)(diag)-202, DTC P0351 IGNITION COIL

A PRIMARY/SECONDARY CIRCUIT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

15WRX_STI_US_EN.book 204 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-205

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CB:DTC P0365 CAMSHAFT POSITION SENSOR “B” CIRCUIT (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-106, DTC P0365 CAMSHAFT POSITION SENSOR “B” CIR-

CUIT (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

EN-10866

B550

216

B220

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

B137

E65

E62

E65E62

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

EXHAUST CAMSHAFT

POSITION SENSOR RH

EXHAUST CAMSHAFT

POSITION SENSOR LH

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 205 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-206

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY OF CAMSHAFT

POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from camshaft

position sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between camshaft

position sensor connector and engine ground.

Connector & terminal

(E62) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit or

short circuit to

ground in harness

between main re-

lay connector and

camshaft position

sensor connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and camshaft position sensor connector.

Connector & terminal

(B137) No. 23 — (E62) No. 2:

(B137) No. 30 — (E62) No. 3:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the resistance between camshaft

position sensor connector and engine ground.

Connector & terminal

(E62) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair short cir-

cuit to ground in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector.

4 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the voltage between camshaft posi-

tion sensor connector and engine ground.

Connector & terminal

(E62) No. 2 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and cam-

shaft position

sensor connector.

Go to step 5.

5 CHECK CONDITION OF CAMSHAFT POSI-

TION SENSOR.

Is the camshaft position sensor

installation bolt tightened

securely?

Go to step 6. Tighten the cam-

shaft position sen-

sor installation bolt

securely. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

6 CHECK CAMSHAFT POSITION SENSOR.

Check the waveform of the camshaft position

sensor. <Ref. to EN(STI)(diag)-19, Engine Con-

trol Module (ECM) I/O Signal.>

Is there any abnormality in

waveform?

Replace the cam-

shaft position sen-

sor. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

Repair the follow-

ing item.

• Poor contact of

ECM connector

• Poor contact of

camshaft position

sensor connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 206 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-207

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CC:DTC P0366 CAMSHAFT POSITION SENSOR B CIRCUIT RANGE/PERFOR-

MANCE (BANK 1)

NOTE:

For the diagnostic procedure, refer to DTC P0365. <Ref. to EN(STI)(diag)-205, DTC P0365 CAMSHAFT PO-

SITION SENSOR “B” CIRCUIT (BANK 1), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

15WRX_STI_US_EN.book 207 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-208

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CD:DTC P0390 CAMSHAFT POSITION SENSOR “B” CIRCUIT (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-107, DTC P0390 CAMSHAFT POSITION SENSOR “B” CIR-

CUIT (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

EN-10866

B550

216

B220

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

B137

E65

E62

E65E62

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

EXHAUST CAMSHAFT

POSITION SENSOR RH

EXHAUST CAMSHAFT

POSITION SENSOR LH

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 208 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-209

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK POWER SUPPLY OF CAMSHAFT

POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from camshaft

position sensor.

3) Turn the ignition switch to ON.

4) Measure the voltage between camshaft

position sensor connector and engine ground.

Connector & terminal

(E65) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit or

short circuit to

ground in harness

between main re-

lay connector and

camshaft position

sensor connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and camshaft position sensor connector.

Connector & terminal

(B137) No. 29 — (E65) No. 2:

(B137) No. 30 — (E65) No. 3:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the resistance between camshaft

position sensor connector and engine ground.

Connector & terminal

(E65) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair short cir-

cuit to ground in

harness between

ECM connector

and camshaft posi-

tion sensor con-

nector.

4 CHECK HARNESS BETWEEN ECM AND

CAMSHAFT POSITION SENSOR CONNEC-

TOR.

Measure the voltage between camshaft posi-

tion sensor connector and engine ground.

Connector & terminal

(E65) No. 2 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and cam-

shaft position

sensor connector.

Go to step 5.

5 CHECK CONDITION OF CAMSHAFT POSI-

TION SENSOR.

Is the camshaft position sensor

installation bolt tightened

securely?

Go to step 6. Tighten the cam-

shaft position sen-

sor installation bolt

securely. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

6 CHECK CAMSHAFT POSITION SENSOR.

Check the waveform of the camshaft position

sensor. <Ref. to EN(STI)(diag)-19, Engine Con-

trol Module (ECM) I/O Signal.>

Is there any abnormality in

waveform?

Replace the cam-

shaft position sen-

sor. <Ref. to

FU(STI)-35, Cam-

shaft Position Sen-

sor.>

Repair the follow-

ing item.

• Poor contact of

ECM connector

• Poor contact of

camshaft position

sensor connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 209 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-210

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CE:DTC P0391 CAMSHAFT POSITION SENSOR B CIRCUIT RANGE/PERFOR-

MANCE (BANK 2)

NOTE:

For the diagnostic procedure, refer to DTC P0390. <Ref. to EN(STI)(diag)-208, DTC P0390 CAMSHAFT PO-

SITION SENSOR “B” CIRCUIT (BANK 2), Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

15WRX_STI_US_EN.book 210 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-211

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CF:DTC P0410 SECONDARY AIR INJECTION SYSTEM

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-108, DTC P0410 SECONDARY AIR INJECTION SYSTEM,

Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 211 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-212

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK SECONDARY AIR PUMP FUSE.

Check if the secondary air pump fuse (60 A) is

blown out.

Is the fuse blown out? Go to step 2. Go to step 3.

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 212 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-213

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN FUSE BOX

AND SECONDARY AIR PUMP CONNECTOR.

1) Remove the secondary air pump fuse from

the fuse box.

2) Disconnect the secondary air pump con-

nector.

3) Measure the resistance between the sec-

ondary air pump fuse and secondary air pump

connector, and chassis ground.

Connector & terminal

(F9) No. 16 — Chassis ground:

(F11) No. 2 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the fuse

with a new part,

and connect the

secondary air

pump connector.

Go to step 3.

Repair ground

short of the har-

ness between the

fuse box and the

secondary air

pump connector.

3 CHECK SECONDARY AIR PUMP OPERA-

TION.

CAUTION:

Try your best to complete the confirmation

process of this inspection in one try. This in-

spection will put a heavy workload on the

secondary air pump, so the continuous op-

eration may cause damage to the pump. Do

not operate the pump continuously for more

than three times. If you need to operate the

pump further, turn the ignition switch to

OFF and wait for at least two hours.

1) Install the delivery mode fuse.

2) Turn the ignition switch to ON.

3) Perform operation check for the secondary

air pump using the Subaru Select Monitor.

NOTE:

• The compulsory operation using the Subaru

Select Monitor is performed only for 10 seconds

in order to protect the secondary air pump.

When you want to operate the pump again, dis-

connect the ground cable from battery, wait at

least one minute, and perform the clear memo-

ry operation of ECM. Then, perform the forced

operation using the Subaru Select Monitor.

• For detailed procedures, refer to “System Op-

eration Check Mode”. <Ref. to EN(STI)(diag)-

60, System Operation Check Mode.>

Does the secondary air pump

operate?

Go to step 4. Go to step 5.

4 CHECK DUCT BETWEEN SECONDARY AIR

PUMP AND COMBINATION VALVE.

Check the duct between secondary air pump

and combination valve.

Is there damage, clog or dis-

connection of the duct?

Replace, clean or

connect the duct.

Replace the sec-

ondary air combi-

nation valve LH.

<Ref. to EC(STI)-

54, Secondary Air

Combination

Valve.>

Step Check Yes No

15WRX_STI_US_EN.book 213 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-214

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

5 CHECK POWER SUPPLY TO SECONDARY

AIR PUMP.

1) Turn the ignition switch to OFF.

2) Disconnect the battery negative terminal,

wait for 1 minute, and connect it again.

3) Disconnect the secondary air pump con-

nector.

4) Install the delivery mode fuse.

5) Turn the ignition switch to ON.

6) Using the Subaru Select Monitor, measure

the voltage between the secondary air pump

connector and chassis ground while the sec-

ondary air pump is operating.

NOTE:

• The compulsory operation using the Subaru

Select Monitor is performed only for 10 seconds

in order to protect the secondary air pump.

When you want to operate the pump again, dis-

connect the ground cable from battery, wait at

least one minute, and perform the clear memo-

ry operation of ECM. Then, perform the forced

operation using the Subaru Select Monitor.

• For detailed procedures, refer to “System Op-

eration Check Mode”. <Ref. to EN(STI)(diag)-

60, System Operation Check Mode.>

Connector & terminal

(F11) No. 2 (+) — Chassis ground (–):

Is the voltage 10 V or more? Replace the sec-

ondary air pump.

<Ref. to EC(STI)-

53, Secondary Air

Pump.>

Go to step 6.

6 CHECK HARNESS BETWEEN SECONDARY

AIR PUMP RELAY AND SECONDARY AIR

PUMP CONNECTOR.

1) Turn the ignition switch to OFF.

2) Remove the secondary air pump relay.

3) Measure the resistance of harness between

secondary air pump relay connector and sec-

ondary air pump connector.

Connector & terminal

(F9) No. 11 — (F11) No. 2:

Is the resistance less than 1 Ω? Go to step 7. Repair the open

circuit in harness

between second-

ary air pump relay

connector and sec-

ondary air pump

connector.

7 CHECK HARNESS BETWEEN SECONDARY

AIR PUMP CONNECTOR AND CHASSIS

GROUND.

Measure the resistance of the harness between

secondary air pump connector and chassis

ground.

Connector & terminal

(F11) No. 1 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 8. Repair the open

circuit of the har-

ness between sec-

ondary air pump

connector and

chassis ground.

8 CHECK SECONDARY AIR PUMP RELAY.

1) Connect the battery to terminals No. 12 and

No. 13 of the secondary air pump relay.

2) Measure the resistance between secondary

air pump relay terminals.

Terminals

No. 14 — No. 11:

Is the resistance less than 1 Ω? Go to step 9. Replace the sec-

ondary air pump

relay. <Ref. to

EN(STI)(diag)-8,

Electrical Compo-

nent Location.>

Step Check Yes No

15WRX_STI_US_EN.book 214 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-215

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

9 CHECK SECONDARY AIR PUMP RELAY

POWER SUPPLY.

1) Turn the ignition switch to ON.

2) Measure the voltage between the second-

ary air pump relay connector and chassis

ground.

Connector & terminal

(F9) No. 14 (+) — Chassis ground (–):

(F9) No. 12 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 10. Repair the open or

ground short circuit

of power supply

circuit.

10 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR PUMP RELAY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the ECM connector.

3) Measure the resistance of harness between

ECM connector and secondary air pump relay

connector.

Connector & terminal

(B135) No. 27 — (F9) No. 13:

Is the resistance less than 1 Ω? Repair the poor

contact of ECM

connector.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

pump relay con-

nector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 215 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-216

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CG:DTC P0411 SECONDARY AIR INJECTION SYSTEM INCORRECT FLOW DE-

TECTED

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-114, DTC P0411 SECONDARY AIR INJECTION SYSTEM

INCORRECT FLOW DETECTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK SECONDARY AIR COMBINATION

VALVE.

Check the pipe between the secondary air com-

bination valve and cylinder head.

Is there damage or disconnec-

tion of the pipe?

Replace the pipe

between second-

ary air combination

valve and cylinder

head. <Ref. to

EC(STI)-54, Sec-

ondary Air Combi-

nation Valve.>

Go to step 2.

2 CHECK SECONDARY AIR COMBINATION

VALVE.

Race the engine at 2,000 rpm to check whether

or not the exhaust leak is heard.

Is there any exhaust leak? Replace the pipe

between second-

ary air combination

valve and cylinder

head. <Ref. to

EC(STI)-54, Sec-

ondary Air Combi-

nation Valve.>

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 216 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-217

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CH:DTC P0413 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE “A”

CIRCUIT OPEN

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-115, DTC P0413 SECONDARY AIR INJECTION SYSTEM

SWITCHING VALVE “A” CIRCUIT OPEN, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 217 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-218

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 218 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-219

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 1 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Remove the secondary air combination

valve relay 1.

4) Measure the resistance of harness between

ECM connector and secondary air combination

valve relay 1 connector.

Connector & terminal

(B135) No. 8 — (F9) No. 2:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

relay 1 connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 1 CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 8 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and secondary air

combination valve

relay 1 connector.

3 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 2 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Remove the secondary air combination

valve relay 2.

4) Measure the resistance of harness between

ECM connector and secondary air combination

valve relay 2 connector.

Connector & terminal

(B135) No. 20 — (F9) No. 9:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

relay 2 connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 2 CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 20 — Chassis ground:

Is the resistance 1 MΩ or

more?

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Repair the short

circuit to ground in

harness between

ECM connector

and secondary air

combination valve

relay 2 connector.

15WRX_STI_US_EN.book 219 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-220

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CI: DTC P0414 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE “A”

CIRCUIT SHORTED

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-116, DTC P0414 SECONDARY AIR INJECTION SYSTEM

SWITCHING VALVE “A” CIRCUIT SHORTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 220 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-221

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 221 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-222

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CJ:DTC P0416 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE “B”

CIRCUIT OPEN

NOTE:

For the diagnostic procedure, refer to DTC P0413. <Ref. to EN(STI)(diag)-217, DTC P0413 SECONDARY

AIR INJECTION SYSTEM SWITCHING VALVE “A” CIRCUIT OPEN, Diagnostic Procedure with Diagnostic

Trouble Code (DTC).>

CK:DTC P0417 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE “B”

CIRCUIT SHORTED

NOTE:

For the diagnostic procedure, refer to DTC P0414. <Ref. to EN(STI)(diag)-220, DTC P0414 SECONDARY

AIR INJECTION SYSTEM SWITCHING VALVE “A” CIRCUIT SHORTED, Diagnostic Procedure with Diag-

nostic Trouble Code (DTC).>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 1 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Remove the secondary air combination

valve relay 1.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 8 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and secondary air

combination valve

relay 1 connector.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 2 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Remove the secondary air combination

valve relay 2.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 20 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and secondary air

combination valve

relay 2 connector.

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 222 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-223

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CL:DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-117, DTC P0420 CATALYST SYSTEM EFFICIENCY BE-

LOW THRESHOLD (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Idle mixture is out of specifications.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 223 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-224

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK EXHAUST SYSTEM.

Check for gas leaks or air suction caused by

loose or dislocated nuts and bolts, and open

hole at exhaust pipes.

NOTE:

Check the following positions.

• Between cylinder head and front exhaust

pipe

• Between front exhaust pipe and front catalytic

converter

• Between front catalytic converter and rear

catalytic converter

• Loose or improperly attached front oxygen

(A/F) sensor or rear oxygen sensor

Is there any fault in exhaust

system?

Repair or replace

the exhaust sys-

tem. <Ref. to

EX(STI)-2, Gen-

eral Description.>

Go to step 2.

2 CHECK WAVEFORM DATA ON THE SUBA-

RU SELECT MONITOR (WHILE DRIVING).

1) Drive at a constant speed between 80 —

112 km/h (50 — 70 MPH).

2) After 5 minutes have elapsed in the condi-

tion of step 1), use the Subaru Select Monitor

while still driving to read the waveform data.

• At normal condition

• At abnormal condition (numerous inversion)

Is a normal waveform dis-

played?

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Go to step 3.

EN-06666

1.5

0.5

10 sec/div

REAR OXYGEN

SENSOR VOLTAGE

(V)

A/F SENSOR

OUTPUT LAMBDA 1

EN-06667

1.5

0.5

10 sec/div

REAR OXYGEN

SENSOR VOLTAGE

(V)

A/F SENSOR

OUTPUT LAMBDA 1

15WRX_STI_US_EN.book 224 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-225

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

3 CHECK WAVEFORM DATA ON THE SUBA-

RU SELECT MONITOR (WHILE IDLING).

1) Run the engine at idle.

2) In the condition of step 1), use the Subaru

Select Monitor to read the waveform data.

• At normal condition

• At abnormal condition 1 (numerous inversion)

• At abnormal condition 2 (noise input)

Is a normal waveform dis-

played?

Go to step 4. • The waveform is

displayed at abnor-

mal condition 1: Go

to step 4.

• The waveform is

displayed at abnor-

mal condition 2: Go

to step 5.

4 CHECK CATALYTIC CONVERTER. Is the catalytic converter dam-

aged?

Replace the cata-

lytic converter.

<Ref. to EC(STI)-

5, Front Catalytic

Converter.>

Go to step 5.

5 CHECK REAR OXYGEN SENSOR CONNEC-

TOR AND COUPLING CONNECTOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 6.

Step Check Yes No

EN-06668

10 sec/div

REAR OXYGEN

SENSOR VOLTAGE

(V)

EN-06669

10 sec/div

REAR OXYGEN

SENSOR VOLTAGE

(V)

EN-06670

10 sec/div

REAR OXYGEN

SENSOR VOLTAGE

(V)

15WRX_STI_US_EN.book 225 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-226

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 7. Repair the harness

and connector.

NOTE:

Repair the follow-

ing locations.

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

7 CHECK REAR OXYGEN SENSOR SHIELD.

1) Turn the ignition switch to OFF.

2) Expose the rear oxygen sensor connector

body side harness sensor shield.

3) Measure the resistance between sensor

shield and chassis ground.

Is the resistance less than 1 Ω? Go to step 8. Repair the open

circuit of rear oxy-

gen sensor har-

ness.

8 CHECK ENGINE OIL AMOUNT AND EX-

HAUST GAS.

1) Check the engine oil amount. <Ref. to

LU(STI)-11, INSPECTION, Engine Oil.>

2) Check exhaust gas during idling.

Does the engine oil amount

drop or white smoke emit from

the muffler?

Check the engine,

and repair the

defective part.

<Ref. to ME(STI)-

107, INSPEC-

TION, Engine

Trouble in Gen-

eral.>

After repairing the

engine, replace the

catalytic con-

verter. <Ref. to

EX(STI)-7, Center

Exhaust Pipe.>

After the catalytic

converter is

replaced, perform

step 2 to check the

normal waveform

is displayed, and

then exit the proce-

dure.

Go to step 9.

9 CHECK IGNITION SYSTEM.

1) Check the spark plug. <Ref. to IG(STI)-5,

INSPECTION, Spark Plug.>

2) Check the status of the ignition coil connec-

tor and the spark plug terminal.

Is there any fault in the ignition

system?

After repairing the

ignition system,

replace the cata-

lytic converter.

<Ref. to EX(STI)-7,

Center Exhaust

Pipe.>

After the catalytic

converter is

replaced, perform

step 2 to check the

normal waveform

is displayed, and

then exit the proce-

dure.

Go to step 10.

Step Check Yes No

15WRX_STI_US_EN.book 226 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-227

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

10 CHECK FUEL SYSTEM.

1) Refer to and check the items in “Insufficient

fuel supply to fuel injector” (except for “a. Fuel

pump does not operate.”) and “Leakage or blow

out of fuel”. <Ref. to FU(STI)-100, INSPEC-

TION, Fuel System Trouble in General.>

2) Check throttle body. <Ref. to FU(STI)-15,

INSPECTION, Throttle Body.>

3) Check intake manifold. <Ref. to FU(STI)-32,

INSPECTION, Intake Manifold.>

Is there any fault in the fuel sys-

tem?

After repairing the

fuel system,

replace the cata-

lytic converter.

<Ref. to EX(STI)-7,

Center Exhaust

Pipe.>

After the catalytic

converter is

replaced, perform

step 2 to check the

normal waveform

is displayed, and

then exit the proce-

dure.

Go to step 11.

11 CHECK DTC. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

After checking the

DTC, replace the

catalytic con-

verter. <Ref. to

EX(STI)-7, Center

Exhaust Pipe.>

After the catalytic

converter is

replaced, perform

step 2 to check the

normal waveform

is displayed, and

then exit the proce-

dure.

Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Step Check Yes No

15WRX_STI_US_EN.book 227 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-228

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CM:DTC P0441 EVAPORATIVE EMISSION CONT. SYS. INCORRECT PURGE

FLOW

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-119, DTC P0441 EVAPORATIVE EMISSION CONT. SYS.

INCORRECT PURGE FLOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK PURGE CONTROL SOLENOID

VALVE.

Operate the purge control solenoid valve using

the Subaru Select Monitor.

NOTE:

For detailed procedures, refer to “System Oper-

ation Check Mode”. <Ref. to EN(STI)(diag)-60,

System Operation Check Mode.>

Does the purge control sole-

noid valve operate?

Go to step 3. Replace the purge

control solenoid

valve. <Ref. to

EC(STI)-22, Purge

Control Solenoid

Valve.>

3 CHECK EVAPORATIVE EMISSION CON-

TROL SYSTEM LINE.

1) Turn the ignition switch to OFF.

2) Make sure that the delivery mode fuse is

removed.

Are there holes, cracks, clog-

ging, or disconnection, miscon-

nection of hoses or pipes in

evaporative emission control

system?

Repair or replace

the hoses or pipes.

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 228 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-229

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CN:DTC P0451 EVAPORATIVE EMISSION SYSTEM PRESSURE SENSOR/

SWITCH RANGE/PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-121, DTC P0451 EVAPORATIVE EMISSION SYSTEM

PRESSURE SENSOR/SWITCH RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Cri-

teria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK CURRENT DATA.

1) Turn the ignition switch to ON (engine OFF).

2) Using the Subaru Select Monitor or general

scan tool, read the value in «Atmosphere Pres-

sure» and «Mani. Absolute Pressure», and

compare them with the actual atmospheric

pressure.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

• To read the actual atmospheric pressure,

connect the Subaru Select Monitor or general

scan tool to the other known good vehicle.

Is the difference with the actual

atmospheric pressure 3.3 kPa

(24.5 mmHg, 1 inHg) or more?

Replace the part

that showed larger

deviation from the

actual atmospheric

pressure than the

other.

• If deviations in

value for «Atmo-

sphere Pressure»

is larger: Replace

the leak check

valve assembly.

<Ref. to EC(STI)-

30, Leak Check

Valve Assembly.>

• If deviations in

value for «Mani.

Absolute Pres-

sure» is larger:

Replace the mani-

fold absolute pres-

sure sensor. <Ref.

to FU(STI)-41,

Manifold Absolute

Pressure Sensor.>

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 229 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-230

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CO:DTC P0452 EVAPORATIVE EMISSION SYSTEM PRESSURE SENSOR/

SWITCH LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-123, DTC P0452 EVAPORATIVE EMISSION SYSTEM

PRESSURE SENSOR/SWITCH LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 230 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-231

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Turn the ignition switch to ON.

2) Read the value of «Atmosphere Pressure»

using the Subaru Select Monitor or a general

scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value in «Atmosphere

Pressure» 34 kPa (255 mmHg,

10 inHg) or less?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK POWER SUPPLY OF LEAK CHECK

VALVE ASSEMBLY.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the leak

check valve assembly.

3) Turn the ignition switch to ON.

4) Measure the voltage between the leak

check valve assembly connector and chassis

ground.

Connector & terminal

(R400) No. 6 (+) — Chassis ground (–):

Is the voltage 4.5 V or more? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the leak check

valve assembly

connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 21 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair the short

circuit to ground in

harness between

ECM connector

and leak check

valve assembly

connector.

4 CHECK FOR POOR CONTACT.

Check for poor contact of leak check valve

assembly connector.

Is there poor contact in the leak

check valve assembly connec-

tor?

Repair the poor

contact in the leak

check valve

assembly connec-

tor.

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

15WRX_STI_US_EN.book 231 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-232

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CP:DTC P0453 EVAPORATIVE EMISSION SYSTEM PRESSURE SENSOR/

SWITCH HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-124, DTC P0453 EVAPORATIVE EMISSION SYSTEM

PRESSURE SENSOR/SWITCH HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 232 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-233

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Turn the ignition switch to ON.

2) Read the value of «Atmosphere Pressure»

using the Subaru Select Monitor or a general

scan tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value in «Atmosphere

Pressure» 125 kPa (938

mmHg, 36.9 inHg) or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

the leak check valve assembly.

3) Measure the resistance of harness between

ECM connector and the leak check valve

assembly connector.

Connector & terminal

(B136) No. 21 — (R400) No. 7:

(B135) No. 30 — (R400) No. 8:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the leak check

valve assembly

connector

• Poor contact of

coupling connector

• Poor contact of

joint connector

3 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and the leak

check valve assembly connector.

Is there poor contact in ECM

and the leak check valve

assembly connector?

Repair the poor

contact of ECM

and the leak check

valve assembly

connector.

Go to step 4.

4 CHECK LEAK CHECK VALVE ASSEMBLY.

Check the pressure sensor of the leak check

valve assembly. <Ref. to EC(STI)-47, CHECK

PRESSURE SENSOR, INSPECTION, Leak

Check Valve Assembly.>

Is the pressure sensor of the

leak check valve assembly OK?

Repair the short

circuit to power in

harness between

ECM connector

and leak check

valve assembly

connector.

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

15WRX_STI_US_EN.book 233 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-234

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CQ:DTC P0455 EVAPORATIVE EMISSION SYSTEM LEAK DETECTED (LARGE

LEAK)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-125, DTC P0455 EVAPORATIVE EMISSION SYSTEM

LEAK DETECTED (LARGE LEAK), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Fuel odor

• There is a hole of more than 1.0 mm (0.04 in) dia. in evaporation system or fuel tank.

• Fuel filler cap loose or lost

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FUEL FILLER CAP.

1) Turn the ignition switch to OFF.

2) Check the fuel filler cap.

NOTE:

The DTC is stored in memory if fuel filler cap is

or was loose or if the cap chain has caught while

tightening.

Is the fuel filler cap tightened

securely?

Go to step 2. Tighten fuel filler

cap securely.

2 CHECK FUEL FILLER CAP. Is the fuel filler cap genuine? Go to step 3. Replace with a

genuine fuel filler

cap.

3 CHECK FUEL FILLER PIPE GASKET. Is there any damage to the seal

between fuel filler cap and fuel

filler pipe?

Repair or replace

the fuel filler cap

and fuel filler pipe.

<Ref. to FU(STI)-

77, Fuel Filler

Pipe.>

Go to step 4.

4 CHECK PURGE CONTROL SOLENOID

VALVE.

Check air-tightness of the purge control sole-

noid valve. <Ref. to EC(STI)-23, INSPECTION,

Purge Control Solenoid Valve.>

Is the purge control solenoid

valve OK?

Go to step 5. Replace the purge

control solenoid

valve. <Ref. to

EC(STI)-22, Purge

Control Solenoid

Valve.>

5 CHECK EVAPORATIVE EMISSION CON-

TROL SYSTEM LINE.

Are there holes on the evapora-

tion line?

Repair or replace

the evaporation

line. <Ref. to

FU(STI)-94, Fuel

Delivery, Return

and Evaporation

Lines.>

Go to step 6.

6 CHECK CANISTER. Are there holes on the canis-

ter?

Replace the canis-

ter. <Ref. to

EC(STI)-7, Canis-

ter.>

Go to step 7.

7 CHECK LEAK CHECK VALVE ASSEMBLY. Are there damage or holes on

the leak check valve assembly?

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Go to step 8.

15WRX_STI_US_EN.book 234 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-235

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CR:DTC P0456 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECT-

ED (VERY SMALL LEAK)

NOTE:

For the diagnostic procedure, refer to DTC P0455. <Ref. to EN(STI)(diag)-234, DTC P0455 EVAPORATIVE

EMISSION SYSTEM LEAK DETECTED (LARGE LEAK), Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

8 CHECK FUEL TANK.

Remove the fuel tank. <Ref. to FU(STI)-67, Fuel

Tank.>

Are there damage or holes on

the fuel tank?

Repair or replace

the fuel tank. <Ref.

to FU(STI)-67,

Fuel Tank.>

Go to step 9.

9 CHECK ANY OTHER MECHANICAL TROU-

BLE IN EVAPORATIVE EMISSION CON-

TROL SYSTEM.

Are there holes, cracks, clog-

ging, or disconnection, miscon-

nection of hoses or pipes in

evaporative emission control

system?

Repair or replace

the hoses or pipes.

Repair the poor

contact of ECM

connector.

Step Check Yes No

15WRX_STI_US_EN.book 235 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-236

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CS:DTC P0458 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE

CIRCUIT LOW

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-131, DTC P0458 EVAPORATIVE EMISSION SYSTEM

PURGE CONTROL VALVE CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 2. Go to step 3.

E52

B137

EN-10869

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

E52

B21 E2

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

PURGE CONTROL

SOLENOID VALVE 2

PURGE CONTROL

SOLENOID VALVE 1

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 236 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-237

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary open or

short circuit of har-

ness or temporary

poor contact of

connector may be

the cause.

3 CHECK POWER SUPPLY TO PURGE CON-

TROL SOLENOID VALVE CONNECTOR.

Measure the voltage between purge control

solenoid valve connector and engine ground.

Connector & terminal

(E4) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 4. Repair the power

supply circuit.

4 CHECK HARNESS BETWEEN ECM AND

PURGE CONTROL SOLENOID VALVE CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

purge control solenoid valve.

3) Measure the resistance between the purge

control solenoid valve connector and engine

ground.

Connector & terminal

(E4) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and purge control

solenoid valve con-

nector.

5 CHECK HARNESS BETWEEN ECM AND

PURGE CONTROL SOLENOID VALVE CON-

NECTOR.

Measure the resistance of harness between

ECM connector and purge control solenoid

valve connector.

Connector & terminal

(B137) No. 6 — (E4) No. 2:

Is the resistance less than 1 Ω? Go to step 6. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and purge control

solenoid valve

connector

• Poor contact of

coupling connector

6 CHECK PURGE CONTROL SOLENOID

VALVE.

1) Remove the purge control solenoid valve.

2) Measure the resistance between purge con-

trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 10 — 100 Ω? Repair the poor

contact of purge

control solenoid

valve connector.

Replace the purge

control solenoid

valve. <Ref. to

EC(STI)-22, Purge

Control Solenoid

Valve.>

Step Check Yes No

15WRX_STI_US_EN.book 237 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-238

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CT:DTC P0459 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE

CIRCUIT HIGH

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-132, DTC P0459 EVAPORATIVE EMISSION SYSTEM

PURGE CONTROL VALVE CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

PURGE CONTROL SOLENOID VALVE CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

purge control solenoid valve.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and purge

control solenoid

valve connector.

Go to step 2.

E52

B137

EN-10869

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

E52

B21 E2

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

PURGE CONTROL

SOLENOID VALVE 2

PURGE CONTROL

SOLENOID VALVE 1

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 238 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-239

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK PURGE CONTROL SOLENOID

VALVE.

1) Turn the ignition switch to OFF.

2) Measure the resistance between purge con-

trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω? Replace the purge

control solenoid

valve. <Ref. to

EC(STI)-22, Purge

Control Solenoid

Valve.>

Repair the poor

contact of ECM

connector.

Step Check Yes No

15WRX_STI_US_EN.book 239 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-240

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CU:DTC P0461 FUEL LEVEL SENSOR “A” CIRCUIT RANGE/PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-133, DTC P0461 FUEL LEVEL SENSOR “A” CIRCUIT

RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

CV:DTC P0462 FUEL LEVEL SENSOR “A” CIRCUIT LOW

NOTE:

For the diagnostic procedure, refer to DTC P0463. <Ref. to EN(STI)(diag)-241, DTC P0463 FUEL LEVEL

SENSOR “A” CIRCUIT HIGH, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Replace the fuel

level sensor and

fuel sub level sen-

sor. <Ref. to

FU(STI)-84, Fuel

Level Sensor.>

<Ref. to FU(STI)-

85, Fuel Sub Level

Sensor.>

15WRX_STI_US_EN.book 240 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-241

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CW:DTC P0463 FUEL LEVEL SENSOR “A” CIRCUIT HIGH

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-135, DTC P0463 FUEL LEVEL SENSOR “A” CIRCUIT

HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is DTC P0462 or P0463 dis-

played on the Subaru Select

Monitor?

Check the combi-

nation meter. <Ref.

to IDI(diag)-2,

Basic Diagnostic

Procedure.>

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 241 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-242

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CX:DTC P04AC EVAP SYSTEM PURGE CONTROL VALVE "B" CIRCUIT LOW

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-136, DTC P04AC EVAP SYSTEM PURGE CONTROL

VALVE "B" CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 2. Go to step 3.

E52

B137

EN-10869

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

E52

B21 E2

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

PURGE CONTROL

SOLENOID VALVE 2

PURGE CONTROL

SOLENOID VALVE 1

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 242 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-243

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary open or

short circuit of har-

ness or temporary

poor contact of

connector may be

the cause.

3 CHECK POWER SUPPLY TO PURGE CON-

TROL SOLENOID VALVE 2 CONNECTOR.

Measure the voltage between purge control

solenoid valve 2 connector and engine ground.

Connector & terminal

(E52) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 4. Repair the power

supply circuit.

4 CHECK HARNESS BETWEEN ECM AND

PURGE CONTROL SOLENOID VALVE 2

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

purge control solenoid valve 2.

3) Measure the resistance between the purge

control solenoid valve 2 connector and engine

ground.

Connector & terminal

(E52) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the ground

short circuit of har-

ness between

ECM connector

and purge control

solenoid valve 2

connector.

5 CHECK HARNESS BETWEEN ECM AND

PURGE CONTROL SOLENOID VALVE 2

CONNECTOR.

Measure the resistance of harness between

ECM connector and purge control solenoid

valve 2 connector.

Connector & terminal

(B137) No. 15 — (E52) No. 2:

Is the resistance less than 1 Ω? Go to step 6. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and purge control

solenoid valve 2

connector

• Poor contact of

coupling connector

6 CHECK PURGE CONTROL SOLENOID

VALVE 2.

1) Remove the purge control solenoid valve 2.

2) Measure the resistance between purge con-

trol solenoid valve 2 terminals.

Terminals

No. 1 — No. 2:

Is the resistance 10 — 100 Ω? Repair the poor

contact of the

purge control sole-

noid valve 2 con-

nector.

Replace the purge

control solenoid

valve 2. <Ref. to

EC(STI)-22, Purge

Control Solenoid

Valve.>

Step Check Yes No

15WRX_STI_US_EN.book 243 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-244

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CY:DTC P04AD EVAP SYSTEM PURGE CONTROL VALVE "B" CIRCUIT HIGH

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-137, DTC P04AD EVAP SYSTEM PURGE CONTROL

VALVE "B" CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

PURGE CONTROL SOLENOID VALVE 2

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

purge control solenoid valve 2.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and purge control

solenoid valve 2

connector.

Go to step 2.

E52

B137

EN-10869

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

E52

B21 E2

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

PURGE CONTROL

SOLENOID VALVE 2

PURGE CONTROL

SOLENOID VALVE 1

MAIN RELAY

BATTERY

FUSE HOLDER

15WRX_STI_US_EN.book 244 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-245

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK PURGE CONTROL SOLENOID

VALVE 2.

1) Turn the ignition switch to OFF.

2) Measure the resistance between purge con-

trol solenoid valve 2 terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω? Replace the purge

control solenoid

valve 2. <Ref. to

EC(STI)-22, Purge

Control Solenoid

Valve.>

Repair the poor

contact of ECM

connector.

Step Check Yes No

15WRX_STI_US_EN.book 245 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-246

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CZ:DTC P04DB CRANKCASE VENTILATION SYSTEM DISCONNECTED

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-138, DTC P04DB CRANKCASE VENTILATION SYSTEM

DISCONNECTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK BLOW-BY HOSE.

Check the blow-by hose condition.

Is there any disconnection or

crack in blow-by hose?

Install or replace

the blow-by hose.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

PCV HOSE ASSEMBLY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM

and PCV hose assembly.

3) Measure the resistance of harness between

ECM connector and PCV hose assembly con-

nector.

Connector & terminal

(B137) No. 12 — (E80) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and PCV hose as-

sembly connector

• Poor contact of

coupling connector

E2B21

E87

E80

EN-10870

E80

E87

B137

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

20 21

28 29

30 31

1413121110

1234567

B137

ECM

LEAK DIAGNOSIS

CONNECTOR 1

LEAK DIAGNOSIS

CONNECTOR 2

15WRX_STI_US_EN.book 246 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-247

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

3 CHECK HARNESS BETWEEN ECM AND

PCV HOSE ASSEMBLY CONNECTOR.

Measure the resistance between PCV hose

assembly connector and chassis ground.

Connector & terminal

(B137) No. 12 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair the short

circuit to ground in

harness between

ECM connector

and PCV hose

assembly connec-

tor.

4 CHECK HARNESS BETWEEN LEAK DIAG-

NOSIS CONNECTORS.

Measure the resistance of harness between

leak diagnosis connectors.

Connector & terminal

(E80) No. 1 — (E87) No. 1:

Is the resistance less than 1 Ω? Go to step 5. Repair the open

circuit in the wiring

harness between

leak diagnosis

connectors.

5 CHECK GROUND CIRCUIT OF PCV HOSE

ASSEMBLY.

Measure the resistance of harness between

PCV hose assembly connector and engine

ground.

Connector & terminal

(E87) No. 2 — Engine ground:

Is the resistance less than 5 Ω? Go to step 6. Repair the open

circuit in harness

between PCV hose

assembly connec-

tor and engine

ground.

6 CHECK PCV HOSE ASSEMBLY.

Measure the resistance between terminals of

each leak diagnosis connector.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω

at all measurement?

Repair the poor

contact of ECM

and PCV hose

assembly connec-

tor.

Replace the PCV

hose assembly.

<Ref. to EC(STI)-

49, PCV Hose

Assembly.>

Step Check Yes No

15WRX_STI_US_EN.book 247 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-248

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DA:DTC P0500 VEHICLE SPEED SENSOR “A”

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-139, DTC P0500 VEHICLE SPEED SENSOR “A”, Diagnos-

tic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK DTC OF VDC.

Check DTC of VDC.

Is DTC of VDC displayed? Perform the diag-

nosis according to

DTC. <Ref. to

VDC(diag)-42, List

of Diagnostic Trou-

ble Code (DTC).>

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 248 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-249

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DB:DTC P0506 IDLE AIR CONTROL SYSTEM RPM LOWER THAN EXPECTED

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-140, DTC P0506 IDLE AIR CONTROL SYSTEM RPM LOW-

ER THAN EXPECTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Hard to start the engine.

• Engine does not start.

• Improper idling

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK AIR CLEANER ELEMENT.

1) Turn the ignition switch to OFF.

2) Check the air cleaner element.

Is there excessive clogging on

air cleaner element?

Replace the air

cleaner element.

<Ref. to IN(STI)-8,

Air Cleaner Ele-

ment.>

Go to step 3.

3 CHECK ELECTRONIC THROTTLE CON-

TROL.

1) Remove the electronic throttle control. <Ref.

to FU(STI)-15, REMOVAL, Throttle Body.>

2) Check the electronic throttle control.

Are foreign matter found inside

electronic throttle control?

Remove foreign

matter from elec-

tronic throttle con-

trol.

Perform the diag-

nosis of DTC

P2101. <Ref. to

EN(STI)(diag)-

344, DTC P2101

THROTTLE

ACTUATOR CON-

TROL MOTOR

CIRCUIT RANGE/

PERFORMANCE,

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

15WRX_STI_US_EN.book 249 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-250

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DC:DTC P0507 IDLE AIR CONTROL SYSTEM RPM HIGHER THAN EXPECTED

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-141, DTC P0507 IDLE AIR CONTROL SYSTEM RPM

HIGHER THAN EXPECTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Engine keeps running at higher speed than specified idle speed.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK AIR INTAKE SYSTEM.

1) Start and idle the engine.

2) Check the following items.

• Loose installation of intake manifold and

throttle body

• Cracks of intake manifold gasket and throttle

body gasket

• Disconnection of vacuum hoses

Is there any fault in air intake

system?

Repair air suction

and leaks.

Go to step 3.

3 CHECK ELECTRONIC THROTTLE CON-

TROL.

1) Turn the ignition switch to OFF.

2) Remove the electronic throttle control. <Ref.

to FU(STI)-15, REMOVAL, Throttle Body.>

3) Check the electronic throttle control.

Are foreign matter found inside

electronic throttle control?

Remove foreign

matter from elec-

tronic throttle con-

trol.

Perform the diag-

nosis of DTC

P2101. <Ref. to

EN(STI)(diag)-

344, DTC P2101

THROTTLE

ACTUATOR CON-

TROL MOTOR

CIRCUIT RANGE/

PERFORMANCE,

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

15WRX_STI_US_EN.book 250 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-251

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DD:DTC P050A COLD START IDLE AIR CONTROL SYSTEM PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-142, DTC P050A COLD START IDLE AIR CONTROL SYS-

TEM PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine keeps running at higher speed than specified idle speed.

• Engine keeps running at a lower speed than the specified idle speed.

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 251 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-252

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B220

B550

216

B21

B134

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B134

10 11 12 13 14 15

72134

19 20 22

28 29

18 2521 23 24

3231

26 27

33 34

EN-10855

E16

E17

E16

E17

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

FUEL INJECTOR No. 4

FUEL INJECTOR No. 3

FUEL INJECTOR No. 2

FUEL INJECTOR No. 1

BATTERY

FUSE HOLDER

MAIN RELAY

15WRX_STI_US_EN.book 252 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-253

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK ENGINE OIL. Is there a proper amount of

engine oil?

Go to step 3. Replace engine oil.

<Ref. to LU(STI)-

11, REPLACE-

MENT, Engine

Oil.>

3 CHECK EXHAUST SYSTEM. Are there holes or loose bolts

on exhaust system?

Repair the exhaust

system.

Go to step 4.

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 253 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-254

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

4 CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or

disconnection of hose on air

intake system?

Repair the air

intake system.

Go to step 5.

5 CHECK FUEL PRESSURE.

WARNING:

Place “NO OPEN FLAMES” signs near the

working area.

CAUTION:

Be careful not to spill fuel.

Measure the fuel pressure while disconnecting

pressure regulator vacuum hose from intake

manifold. <Ref. to ME(STI)-25, INSPECTION,

Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

If fuel pressure does not increase, squeeze the

fuel return hose 2 to 3 times, then measure fuel

pressure again.

Is the measured value 284 —

314 kPa (2.9 — 3.2 kg/cm

, 41

— 46 psi)?

Go to step 6. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

6 CHECK FUEL PRESSURE.

After connecting the pressure regulator vacuum

hose, measure fuel pressure. <Ref. to ME(STI)-

25, INSPECTION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

• If fuel pressure does not increase, squeeze

fuel return hose 2 to 3 times, then measure fuel

pressure again.

• If the measured value at this step is out of

specification, check or replace pressure regula-

tor and pressure regulator vacuum hose.

Is the measured value 230 —

260 kPa (2.4 — 2.7 kg/cm

, 33

— 38 psi)?

Go to step 7. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

7 CHECK ENGINE COOLANT TEMPERATURE

SENSOR.

1) Start the engine and warm up completely.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

75°C (167°F) or more?

Go to step 8. Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

Step Check Yes No

15WRX_STI_US_EN.book 254 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-255

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

8 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Read the value of «Mass Air Flow» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mass Air

Flow» 2.0 — 5.0 g/s (0.26 —

0.66 lb/m)?

Go to step 9. Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

9 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Open the front hood.

6) Measure the ambient temperature.

7) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Subtract ambient temperature

from «Intake Air Temp.». Is the

obtained value –10 — 50°C (–18

— 90°F)?

Go to step 10. Check the mass air

flow and intake air

temperature sen-

sor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

10 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 15. Go to step 11.

Step Check Yes No

15WRX_STI_US_EN.book 255 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-256

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

11 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector

on faulty cylinders.

3) Measure the resistance between fuel injec-

tor connector and engine ground on faulty cylin-

ders.

Connector & terminal

#1 (E5) No. 2 — Engine ground:

#2 (E16) No. 2 — Engine ground:

#3 (E6) No. 2 — Engine ground:

#4 (E17) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 12. Repair the short

circuit to ground in

harness between

ECM connector

and fuel injector

connector.

12 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

Measure the resistance of harness between

ECM connector and fuel injector connector on

faulty cylinders.

Connector & terminal

#1 (B134) No. 10 — (E5) No. 2:

#2 (B134) No. 11 — (E16) No. 2:

#3 (B134) No. 12 — (E6) No. 2:

#4 (B134) No. 13 — (E17) No. 2:

Is the resistance less than 1 Ω? Go to step 13. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and fuel injector

connector

• Poor contact of

coupling connector

13 CHECK FUEL INJECTOR.

Measure the resistance between fuel injector

terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 14. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

14 CHECK POWER SUPPLY LINE.

1) Turn the ignition switch to ON.

2) Measure the voltage between fuel injector

and engine ground on faulty cylinders.

Connector & terminal

#1 (E5) No. 1 (+) — Engine ground (–):

#2 (E16) No. 1 (+) — Engine ground (–):

#3 (E6) No. 1 (+) — Engine ground (–):

#4 (E17) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Repair the poor

contact of all con-

nectors in fuel

injector circuit.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

the main relay con-

nector and fuel in-

jector connector on

faulty cylinders

• Poor contact of

coupling connector

• Poor contact of

main relay connec-

tor

15 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector

on faulty cylinders.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and fuel injector

connectors.

Go to step 16.

Step Check Yes No

15WRX_STI_US_EN.book 256 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-257

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

16 CHECK FUEL INJECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between fuel injec-

tor terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 17. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

17 CHECK INSTALLATION OF CAMSHAFT PO-

SITION SENSOR/CRANKSHAFT POSITION

SENSOR.

Is the camshaft position sensor

or crankshaft position sensor

loosely installed?

Tighten the cam-

shaft position sen-

sor or crankshaft

position sensor.

<Ref. to FU(STI)-

35, Camshaft Posi-

tion Sensor.> <Ref.

to FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

Go to step 18.

18 CHECK CRANK SPROCKET.

Remove the timing belt cover. <Ref. to ME(STI)-

50, REMOVAL, Timing Belt Cover.>

Is the crank sprocket rusted or

does it have broken teeth?

Replace the crank

sprocket. <Ref. to

ME(STI)-61, Crank

Sprocket.>

Go to step 19.

19 CHECK INSTALLATION CONDITION OF

TIMING BELT.

Turn the crankshaft, and align alignment mark

on crank sprocket with alignment mark on cylin-

der block.

ST 499987500 CRANKSHAFT

SOCKET

Is the timing belt dislocated

from its proper position?

Repair the installa-

tion condition of

timing belt. <Ref. to

ME(STI)-51, Tim-

ing Belt.>

Go to step 20.

20 CHECK ELECTRONIC THROTTLE CON-

TROL RELAY.

1) Turn the ignition switch to OFF.

2) Remove the electronic throttle control relay.

3) Connect the battery to terminals No. 16 and

No. 17 of electronic throttle control relay.

4) Measure the resistance between electronic

throttle control relay terminals.

Terminals

No. 15 — No. 16:

Is the resistance less than 1 Ω? Go to step 21. Replace the elec-

tronic throttle con-

trol relay. <Ref. to

FU(STI)-60, Elec-

tronic Throttle

Control Relay.>

21 CHECK POWER SUPPLY OF ELECTRONIC

THROTTLE CONTROL RELAY.

Measure the voltage between electronic throttle

control relay connector and chassis ground.

Connector & terminal

(B225) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 22. Repair the open or

ground short circuit

of power supply

circuit.

22 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Disconnect the connector from ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 17 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

Go to step 23.

Step Check Yes No

15WRX_STI_US_EN.book 257 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-258

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

23 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 14 — Chassis ground:

(B225) No. 17 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 24. Repair the short

circuit to ground in

harness between

ECM connector

and electronic

throttle control

relay connector.

24 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

Measure the resistance between ECM connec-

tor and electronic throttle control relay connec-

tor.

Connector & terminal

(B135) No. 7 — (B225) No. 14:

(B135) No. 17 — (B225) No. 17:

Is the resistance less than 1 Ω? Go to step 25. Repair the open

circuit in harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

25 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 19 — Chassis ground:

(B134) No. 18 — Chassis ground:

(B134) No. 18 — (B136) No. 4:

(B134) No. 28 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 26. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

26 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(B57) No. 6 — Engine ground:

(B57) No. 4 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 27. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

27 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between

ECM connector and electronic throttle control

connector.

Connector & terminal

(B134) No. 18 — (E57) No. 6:

(B134) No. 28 — (E57) No. 4:

(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 Ω? Go to step 28. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 258 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-259

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

28 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step 29. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

29 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 6 (+) — Engine ground (–):

(E57) No. 4 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 30.

30 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B134) No. 19 — (B134) No. 18:

(B134) No. 19 — (B134) No. 28:

Is the resistance 1 MΩ or

more?

Go to step 31. Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

31 CHECK SENSOR OUTPUT.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) Read the value of «Main-Throttle Sensor»

using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Main-Throttle

Sensor» 0.81 — 0.87 V?

Go to step 32. Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

32 CHECK SENSOR OUTPUT.

Read the value of «Sub-Throttle Sensor» using

Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Sub-Throttle

Sensor» 1.64 — 1.70 V?

Go to step 33. Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

Step Check Yes No

15WRX_STI_US_EN.book 259 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-260

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

33 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL MO-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance between ECM con-

nector and electronic throttle control connector.

Connector & terminal

(B134) No. 1 — (E57) No. 1:

(B134) No. 2 — (E57) No. 2:

Is the resistance less than 1 Ω? Go to step 34. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

34 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL MO-

TOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 1 (+) — Engine ground (–):

(E57) No. 2 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 35.

35 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL MO-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 1 — Engine ground:

(E57) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 36. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

36 CHECK ELECTRONIC THROTTLE CON-

TROL MOTOR HARNESS.

Measure the resistance between electronic

throttle control connectors.

Connector & terminal

(E57) No. 1 — (E57) No. 2:

Is the resistance 1 MΩ or

more?

Go to step 37. Repair the short

circuit in harness

between ECM con-

nector and elec-

tronic throttle

control connector.

37 CHECK ELECTRONIC THROTTLE CON-

TROL GROUND CIRCUIT.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:

(B134) No. 4 — Chassis ground:

(B134) No. 6 — Chassis ground:

(B137) No. 1 — Chassis ground:

(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 38. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

coupling connector

38 CHECK ELECTRONIC THROTTLE CON-

TROL.

Measure the resistance between electronic

throttle control terminals.

Terminals

No. 1 — No. 2:

Is the resistance 50 Ω or less? Go to step 39. Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

Step Check Yes No

15WRX_STI_US_EN.book 260 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-261

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DE:DTC P050B COLD START IGNITION TIMING PERFORMANCE

NOTE:

For the diagnostic procedure, refer to DTC P050A. <Ref. to EN(STI)(diag)-251, DTC P050A COLD START

IDLE AIR CONTROL SYSTEM PERFORMANCE, Diagnostic Procedure with Diagnostic Trouble Code

(DTC).>

39 CHECK ELECTRONIC THROTTLE CON-

TROL.

Move the throttle valve to the fully open and fully

closed positions with fingers.

Check that the valve returns to the specified

position when releasing fingers.

Does the valve return to the

specified position? Standard

value: 3 mm (0.12 in) from fully

closed position

Repair the poor

contact of ECM

connector.

Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

Step Check Yes No

15WRX_STI_US_EN.book 261 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-262

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DF:DTC P0512 STARTER REQUEST CIRCUIT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-145, DTC P0512 STARTER REQUEST CIRCUIT, Diagnos-

tic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 262 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-263

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

B23

12345

6789

B550

228

B136C:

B135B:

B14

B574C:

B572A:

B28B23

B106

B225

39 38

36 37

B225

19 20 21 22 23 24 25 26 27 28 29 30

789

10 11 12 13 14 15 16 17 18

123 456

B574C:

11 12

13 14

15 16

17 18

B572A:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

3231

1234

2726

33 34 35

B136C:

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

B575

123

456789

10 11

12 13 14 15 16 17 18 19 20 21 22

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B106

EN-10852

B14

B550

1024

B225

B34

B26

C16

C27

B576B575

101

242322 272625212019

432

698

11 12

B550

SBF-6

STARTER CUT

RELAY

FUSE

HOLDER

BATTERY

MAIN SBF

IG RELAY 1

(PUSH BUTTON

START)

F/B No. 26

STARTER RELAY

(PUSH BUTTON START)

STARTER

RELAY

CLUTCH START SWITCH

F/B No. 21

KEYLESS

ACCESS CM

STARTER MOTOR

FUSE

HOLDER

15WRX_STI_US_EN.book 263 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-264

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK PUSH BUTTON IGNITION SWITCH.

Operate the push button ignition switch.

Does it operate smoothly with-

out catch?

Go to step 2. Replace the push

button ignition

switch. <Ref. to

SL-106, Push But-

ton Ignition

Switch.>

2 CHECK DTC.

1) Clear the memory using the Subaru Select

Monitor. <Ref. to EN(STI)(diag)-59, Clear Mem-

ory Mode.>

2) Start and idle the engine for three minutes

or more.

Is the same DTC as current

diagnosis output?

Go to step 3. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

3 CHECK HARNESS BETWEEN ECM AND

KEYLESS ACCESS CM.

1) Turn the ignition to OFF.

2) Disconnect the connector from ECM.

3) Turn the ignition to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 16 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power

supply in harness

between ECM con-

nector and keyless

access CM con-

nector.

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 264 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-265

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DG:DTC P0560 SYSTEM VOLTAGE

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-146, DTC P0560 SYSTEM VOLTAGE, Diagnostic Trouble

Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B72

B550

216

B550

1024

B220

B134A:

B135B:

B136C:

B137D:

B21

C30

B13

B220 B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B225

36 37

EN-10853

B72

7856

3412

101

242322 272625212019

432

698

11 12

B550

SBF-7

SBF-6

ECM

: WITHOUT PUSH BUTTON START

: WITH PUSH BUTTON START

IG RELAY 1

(PUSH BUTTON

START)

BATTERY

MAIN

RELAY

FUSE

HOLDER

FUSE

HOLDER

M/B No. 13

F/B No. 12

IGNITION

SWITCH

MAIN SBF

15WRX_STI_US_EN.book 265 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-266

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK INPUT SIGNAL OF ECM.

1) Turn the ignition switch to OFF.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 2 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the poor

contact of ECM

connector.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

MAIN FUSE BOX CONNECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 2 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and battery termi-

nal.

3 CHECK FUSE NO. 13. Is the fuse blown out? Replace the fuse. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and battery

• Poor contact of

ECM connector

• Poor contact of

battery terminal

15WRX_STI_US_EN.book 266 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-267

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DH:DTC P0604 INTERNAL CONTROL MODULE RANDOM ACCESS MEMORY

(RAM) ERROR

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-147, DTC P0604 INTERNAL CONTROL MODULE RAN-

DOM ACCESS MEMORY (RAM) ERROR, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine does not start.

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

DI: DTC P0605 INTERNAL CONTROL MODULE READ ONLY MEMORY (ROM)

ERROR

NOTE:

For the diagnostic procedure, refer to DTC P0606. <Ref. to EN(STI)(diag)-268, DTC P0606 CONTROL

MODULE PROCESSOR, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 267 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-268

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DJ:DTC P0606 CONTROL MODULE PROCESSOR

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-149, DTC P0606 CONTROL MODULE PROCESSOR, Di-

agnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10871

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B122

J/C

B550

216

B220

1110

B134A:

B136C:

B137D:

A18

A19

A28

A29

E57

B21

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

ELECTRONIC THROTTLE

CONTROL

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

MAIN RELAY

FUSE HOLDER

15WRX_STI_US_EN.book 268 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-269

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DK:DTC P060A INTERNAL CONTROL MODULE MONITORING PROCESSOR

PERFORMANCE

NOTE:

For the diagnostic procedure, refer to DTC P0606. <Ref. to EN(STI)(diag)-268, DTC P0606 CONTROL

MODULE PROCESSOR, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

DL:DTC P060B INTERNAL CONTROL MODULE A/D PROCESSING PERFOR-

MANCE

NOTE:

For the diagnostic procedure, refer to DTC P0606. <Ref. to EN(STI)(diag)-268, DTC P0606 CONTROL

MODULE PROCESSOR, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

Step Check Yes No

1 CHECK INPUT VOLTAGE OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (–):

(B137) No. 7 (+) — Chassis ground (–):

Is the voltage 10 — 13 V? Go to step 2. Repair the open or

ground short circuit

of power supply

circuit.

2 CHECK INPUT VOLTAGE OF ECM.

1) Start the engine.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (–):

(B137) No. 7 (+) — Chassis ground (–):

Is the voltage 13 — 15 V? Go to step 3. Repair the open or

ground short circuit

of power supply

circuit.

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance of harness between

ECM connector and electronic throttle control

connector.

Connector & terminal

(B134) No. 19 — (E57) No. 5:

(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

4 CHECK ECM GROUND HARNESS.

1) Connect all connectors.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 3 (+) — Chassis ground (–):

(B134) No. 4 (+) — Chassis ground (–):

(B134) No. 6 (+) — Chassis ground (–):

(B137) No. 1 (+) — Chassis ground (–):

(B137) No. 3 (+) — Chassis ground (–):

Is the voltage less than 1 V? Check the connec-

tor for poor contact

and check the har-

ness.

Replace the ECM if

no fault is found.

<Ref. to FU(STI)-

56, Engine Control

Module (ECM).>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

ground circuit

• Further tighten-

ing of the engine

ground terminal

• Poor contact of

ECM connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 269 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-270

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DM:DTC P0616 STARTER RELAY CIRCUIT LOW

1. MODEL WITHOUT PUSH BUTTON START

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-155, DTC P0616 STARTER RELAY CIRCUIT LOW, Diag-

nostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, ENGINE

TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B72

7856

3412

22 8

B550

B225

B14

B106

B72

B136C:

B135B:

B14

B106

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

3231

1234

2726

33 34 35

B136C:

B135B:

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

EN-10851

B26

C16

101

242322 272625212019

432

698

11 12

B550

SBF-6

ECM

BATTERY

IGNITION SWITCH

F/B No. 21

MAIN SBF

CLUTCH START

SWITCH

STARTER MOTOR

STARTER

RELAY

FUSE HOLDER

15WRX_STI_US_EN.book 270 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-271

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2. MODEL WITH PUSH BUTTON START

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-155, DTC P0616 STARTER RELAY CIRCUIT LOW, Diag-

nostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check DTC using

“List of Diagnostic

Trouble Code

(DTC)”. <Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

STARTER RELAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Remove the starter relay.

3) Disconnect the connectors from ECM and

starter motor.

4) Measure the resistance of harness between

ECM connector and starter relay connector.

Connector & terminal

(B136) No. 16 — (B225) No. 1:

Is the resistance less than 1 Ω? Go to step 3.NOTE:

Check the follow-

ing item and repair

or replace if neces-

sary.

• Open circuit of

harness between

ECM connector

and starter relay

connector

• Blown out of fuse

3 CHECK HARNESS BETWEEN ECM AND

STARTER RELAY CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 16 — Chassis ground:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of ECM

connector.

Repair the short

circuit to ground in

harness between

ECM connector

and starter relay

connector.

15WRX_STI_US_EN.book 271 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-272

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

B23

12345

6789

B550

228

B136C:

B135B:

B14

B574C:

B572A:

B28B23

B106

B225

39 38

36 37

B225

19 20 21 22 23 24 25 26 27 28 29 30

789

10 11 12 13 14 15 16 17 18

123 456

B574C:

11 12

13 14

15 16

17 18

B572A:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

3231

1234

2726

33 34 35

B136C:

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

B575

123

456789

10 11

12 13 14 15 16 17 18 19 20 21 22

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B106

EN-10852

B14

B550

1024

B225

B34

B26

C16

C27

B576B575

101

242322 272625212019

432

698

11 12

B550

SBF-6

STARTER CUT

RELAY

FUSE

HOLDER

BATTERY

MAIN SBF

IG RELAY 1

(PUSH BUTTON

START)

F/B No. 26

STARTER RELAY

(PUSH BUTTON START)

STARTER

RELAY

CLUTCH START SWITCH

F/B No. 21

KEYLESS

ACCESS CM

STARTER MOTOR

FUSE

HOLDER

15WRX_STI_US_EN.book 272 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-273

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

STARTER RELAY CONNECTOR.

1) Turn the ignition to OFF.

2) Disconnect the connector from ECM.

3) Remove the starter relay.

4) Measure the resistance of harness between

ECM connector and starter relay connector.

Connector & terminal

(B136) No. 27 — (B225) No. 1:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and starter relay

connector

• Blown out of fuse

2 CHECK HARNESS BETWEEN ECM AND

STARTER RELAY CONNECTOR.

1) Disconnect the connector from starter

motor.

2) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 27 — Chassis ground:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of ECM

connector.

Repair the short

circuit to ground in

harness between

ECM connector

and starter relay

connector.

15WRX_STI_US_EN.book 273 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-274

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DN:DTC P0617 STARTER RELAY CIRCUIT HIGH

1. MODEL WITHOUT PUSH BUTTON START

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-156, DTC P0617 STARTER RELAY CIRCUIT HIGH, Diag-

nostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, ENGINE

TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B72

7856

3412

22 8

B550

B225

B14

B106

B72

B136C:

B135B:

B14

B106

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

3231

1234

2726

33 34 35

B136C:

B135B:

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

EN-10851

B26

C16

101

242322 272625212019

432

698

11 12

B550

SBF-6

ECM

BATTERY

IGNITION SWITCH

F/B No. 21

MAIN SBF

CLUTCH START

SWITCH

STARTER MOTOR

STARTER

RELAY

FUSE HOLDER

15WRX_STI_US_EN.book 274 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-275

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2. MODEL WITH PUSH BUTTON START

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-156, DTC P0617 STARTER RELAY CIRCUIT HIGH, Diag-

nostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

STARTER RELAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 16 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and starter relay

connector.

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 275 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-276

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

B23

12345

6789

B550

228

B136C:

B135B:

B14

B574C:

B572A:

B28B23

B106

B225

39 38

36 37

B225

19 20 21 22 23 24 25 26 27 28 29 30

789

10 11 12 13 14 15 16 17 18

123 456

B574C:

11 12

13 14

15 16

17 18

B572A:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

3231

1234

2726

33 34 35

B136C:

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

B575

123

456789

10 11

12 13 14 15 16 17 18 19 20 21 22

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B106

EN-10852

B14

B550

1024

B225

B34

B26

C16

C27

B576B575

101

242322 272625212019

432

698

11 12

B550

SBF-6

STARTER CUT

RELAY

FUSE

HOLDER

BATTERY

MAIN SBF

IG RELAY 1

(PUSH BUTTON

START)

F/B No. 26

STARTER RELAY

(PUSH BUTTON START)

STARTER

RELAY

CLUTCH START SWITCH

F/B No. 21

KEYLESS

ACCESS CM

STARTER MOTOR

FUSE

HOLDER

15WRX_STI_US_EN.book 276 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-277

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK STARTER MOTOR.

1) Turn the ignition to ON.

2) Check the starter motor condition.

Is the starter motor rotating? Go to step 2. Repair the short

circuit to power

supply.

NOTE:

In this case, repair

the following har-

nesses:

• Short circuit to

power supply in

harness between

ECM connector

and starter relay

connector

• Short circuit to

power supply in

harness between

ECM connector

and starter motor

• Short circuit to

power supply in

harness between

starter relay con-

nector and starter

motor

2 CHECK HARNESS BETWEEN STARTER

CUT RELAY CONNECTOR AND STARTER

RELAY CONNECTOR.

1) Turn the ignition to OFF.

2) Disconnect the connector from starter

motor.

3) Remove the starter cut relay and starter

relay.

4) Turn the ignition to ON.

5) Measure the voltage between starter relay

connector and chassis ground.

Connector & terminal

(B225) No. 2 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power

supply in harness

between starter cut

relay connector

and starter relay

connector.

Go to step 3.

3 CHECK STARTER CUT RELAY.

1) Connect the battery to starter cut relay ter-

minals No. 40 and No. 42.

2) Measure the resistance between starter cut

relay terminals.

Terminals

No. 41 — No. 44:

Is the resistance 1 MΩ or

more?

Go to step 6. Replace the starter

cut relay. <Ref. to

SL-116, Starter

Cut Relay.>

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND

STARTER RELAY CONNECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B135) No. 26 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and starter relay

connector.

5 CHECK STARTER RELAY.

Measure the resistance between starter relay

terminals.

Terminals

No. 1 — No. 2:

Is the resistance 1 MΩ or

more?

Go to step 6. Replace the starter

relay. <Ref. to

EN(STI)(diag)-8,

LOCATION, Elec-

trical Component

Location.>

15WRX_STI_US_EN.book 277 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-278

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DO:DTC P062F INTERNAL CONTROL MODULE EEPROM ERROR

NOTE:

For the diagnostic procedure, refer to DTC P0606. <Ref. to EN(STI)(diag)-268, DTC P0606 CONTROL

MODULE PROCESSOR, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

6 CHECK HARNESS BETWEEN ECM, START-

ER RELAY CONNECTOR AND STARTER

MOTOR.

1) Disconnect the connector from ECM.

2) Turn the ignition to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 27 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power

supply.

NOTE:

In this case, repair

the following har-

nesses:

• Short circuit to

power supply in

harness between

ECM connector

and starter relay

connector

• Short circuit to

power supply in

harness between

ECM connector

and starter motor

• Short circuit to

power supply in

harness between

starter relay con-

nector and starter

motor

Repair the poor

contact of ECM

connector.

Step Check Yes No

15WRX_STI_US_EN.book 278 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-279

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DP:DTC P0685 ECM/PCM POWER RELAY CONTROL CIRCUIT/OPEN

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-159, DTC P0685 ECM/PCM POWER RELAY CONTROL

CIRCUIT/OPEN, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B72

B550

216

B550

1024

B220

B134A:

B135B:

B136C:

B137D:

B21

C30

B13

B220 B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B225

36 37

EN-10853

B72

7856

3412

101

242322 272625212019

432

698

11 12

B550

SBF-7

SBF-6

ECM

: WITHOUT PUSH BUTTON START

: WITH PUSH BUTTON START

IG RELAY 1

(PUSH BUTTON

START)

BATTERY

MAIN

RELAY

FUSE

HOLDER

FUSE

HOLDER

M/B No. 13

F/B No. 12

IGNITION

SWITCH

MAIN SBF

15WRX_STI_US_EN.book 279 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-280

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK ECM CONNECTOR.

Check the connecting condition of ECM con-

nector.

Is the ECM connector correctly

connected?

Go to step 2. Connect the ECM

connector cor-

rectly.

2 CHECK HARNESS BETWEEN ECM AND

MAIN RELAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Remove the main relay.

3) Disconnect the connector from ECM.

4) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B135) No. 13 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and main relay

connector.

3 CHECK HARNESS BETWEEN ECM AND

MAIN RELAY CONNECTOR.

1) Install the main relay.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (–):

(B137) No. 7 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Short circuit to

power supply in

harness between

ECM connector

and main relay

connector

• Defective main

relay

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 280 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-281

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DQ:DTC P081A STARTER DISABLE CIRCUIT LOW

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-160, DTC P081A STARTER DISABLE CIRCUIT LOW, Di-

agnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Failure of engine to start

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 281 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-282

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

B23

12345

6789

B550

228

B136C:

B135B:

B14

B574C:

B572A:

B28B23

B106

B225

39 38

36 37

B225

19 20 21 22 23 24 25 26 27 28 29 30

789

10 11 12 13 14 15 16 17 18

123 456

B574C:

11 12

13 14

15 16

17 18

B572A:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

3231

1234

2726

33 34 35

B136C:

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

B575

123

456789

10 11

12 13 14 15 16 17 18 19 20 21 22

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B106

EN-10852

B14

B550

1024

B225

B34

B26

C16

C27

B576B575

101

242322 272625212019

432

698

11 12

B550

SBF-6

STARTER CUT

RELAY

FUSE

HOLDER

BATTERY

MAIN SBF

IG RELAY 1

(PUSH BUTTON

START)

F/B No. 26

STARTER RELAY

(PUSH BUTTON START)

STARTER

RELAY

CLUTCH START SWITCH

F/B No. 21

KEYLESS

ACCESS CM

STARTER MOTOR

FUSE

HOLDER

15WRX_STI_US_EN.book 282 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-283

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN STARTER RE-

LAY (PUSH BUTTON START) CONNECTOR

AND STARTER CUT RELAY CONNECTOR.

1) Turn the ignition to OFF.

2) Remove the starter relay (push button start)

and starter cut relay.

3) Measure the resistance of harness between

starter relay (push button start) connector and

starter cut relay connector.

Connector & terminal

(B225) No. 28 — (B225) No. 42:

Is the resistance less than 1 Ω? Go to step 2. Repair the open

circuit in harness

between starter

relay (push button

start) connector

and starter cut

relay connector.

2 CHECK HARNESS BETWEEN ECM AND

STARTER CUT RELAY CONNECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between

ECM connector and starter cut relay connector.

Connector & terminal

(B135) No. 34 — (B225) No. 40:

Is the resistance less than 1 Ω? Go to step 3. Repair the open

circuit of harness

between ECM con-

nector and starter

cut relay connec-

tor.

3 CHECK STARTER CUT RELAY.

1) Connect the battery to starter cut relay ter-

minals No. 40 and No. 42.

2) Measure the resistance between starter cut

relay terminals.

Terminals

No. 41 — No. 44:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of ECM

connector.

Replace the starter

cut relay. <Ref. to

SL-116, Starter

Cut Relay.>

15WRX_STI_US_EN.book 283 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-284

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DR:DTC P0851 NEUTRAL SWITCH INPUT CIRCUIT LOW (MT MODEL)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-161, DTC P0851 NEUTRAL SWITCH INPUT CIRCUIT LOW

(MT MODEL), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK INPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Place the shift lever in a position other than

neutral.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 35 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the poor

contact of ECM

connector.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

NEUTRAL POSITION SWITCH CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

neutral position switch.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 35 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the neu-

tral position switch.

<Ref. to

6MT(TY85)-41,

Neutral Position

Switch.>

Repair the short

circuit to ground

harness between

ECM connector

and neutral posi-

tion switch connec-

tor.

EN-10872

123

456

B128

T12

T9B128

T2T12

B122

J/C

B122

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

NEUTRAL POSITION

SWITCH

15WRX_STI_US_EN.book 284 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-285

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DS:DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-162, DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT

HIGH (MT MODEL), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK INPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Place the shift lever in neutral.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 35 (+) — Chassis ground (–):

Is the voltage less than 1 V? Repair the poor

contact of ECM

connector.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

NEUTRAL POSITION SWITCH CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

neutral position switch.

3) Measure the resistance of harness between

ECM connector and transmission harness con-

nector.

Connector & terminal

(B136) No. 35 — (T12) No. 1:

(B136) No. 4 — (T12) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and transmission

harness connector

• Poor contact of

coupling connector

EN-10872

123

456

B128

T12

T9B128

T2T12

B122

J/C

B122

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

NEUTRAL POSITION

SWITCH

15WRX_STI_US_EN.book 285 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-286

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DT:DTC P1160 RETURN SPRING FAILURE

NOTE:

For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(STI)(diag)-344, DTC P2101 THROTTLE AC-

TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic

Trouble Code (DTC).>

3 CHECK NEUTRAL POSITION SWITCH.

1) Place the shift lever in neutral.

2) Measure the resistance between transmis-

sion harness connector terminals.

Connector & terminal

(T2) No. 1 — (T2) No. 2:

Is the resistance less than 1 Ω? Repair the poor

contact of trans-

mission harness

connector.

Replace the neu-

tral position switch.

<Ref. to

6MT(TY85)-41,

Neutral Position

Switch.>

Step Check Yes No

15WRX_STI_US_EN.book 286 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-287

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DU:DTC P1410 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK OPEN

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-164, DTC P1410 SECONDARY AIR INJECTION SYSTEM

SWITCHING VALVE STUCK OPEN, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK SECONDARY AIR COMBINATION

VALVE.

1) Remove the secondary air combination

valve. <Ref. to EC(STI)-54, Secondary Air

Combination Valve.>

2) Blow in air from the secondary air combina-

tion valve air inlet, and check whether there are

leaks at the pipe connections.

Are there air leaks from the pipe

connections?

Replace the sec-

ondary air combi-

nation valve on the

side with the air

leak. <Ref. to

EC(STI)-54, Sec-

ondary Air Combi-

nation Valve.>

Perform the diag-

nostic procedure of

DTC P2440. <Ref.

to EN(STI)(diag)-

413, DTC P2440

SECONDARY AIR

INJECTION SYS-

TEM SWITCHING

VALVE STUCK

OPEN (BANK1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

15WRX_STI_US_EN.book 287 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-288

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DV:DTC P1449 EVAPORATIVE EMISSION CONT. SYS. AIR FILTER CLOG

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-165, DTC P1449 EVAPORATIVE EMISSION CONT. SYS.

AIR FILTER CLOG, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK DRAIN TUBE A AND DRAIN PIPE

BETWEEN LEAK CHECK VALVE ASSEM-

BLY AND DRAIN FILTER.

Is the drain tube A or the drain

pipe between leak check valve

assembly and drain filter

clogged?

Replace the drain

tube A or the drain

pipe between leak

check valve

assembly and

drain filter. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.> <Ref.

to EC(STI)-26,

Drain Filter.>

Go to step 3.

3 CHECK DRAIN FILTER. Is the drain filter clogged? Replace the drain

filter. <Ref. to

EC(STI)-26, Drain

Filter.>

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

15WRX_STI_US_EN.book 288 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-289

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DW:DTC P1451 EVAPORATIVE EMISSION CONT. SYS.

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-166, DTC P1451 EVAPORATIVE EMISSION CONT. SYS.,

Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK DRAIN TUBE BETWEEN CANISTER

AND LEAK CHECK VALVE ASSEMBLY.

Is the drain tube between canis-

ter and leak check valve

assembly clogged?

Replace the drain

tube between the

canister and leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Go to step 2.

2 CHECK HOSES BETWEEN CANISTER AND

FUEL TANK.

Are the hoses between the can-

ister and fuel tank clogged?

Replace the hoses

between the canis-

ter and fuel tank.

<Ref. to EC(STI)-

7, Canister.> <Ref.

to FU(STI)-67,

Fuel Tank.>

Replace the canis-

ter. <Ref. to

EC(STI)-7, Canis-

ter.>

After the operation

is complete, go to

the next step. Go to

step 3.

3 CHECK EVAPORATIVE EMISSION CON-

TROL SYSTEM.

Perform drive cycle I. <Ref. to EN(STI)(diag)-

56, DRIVE CYCLE I, PROCEDURE, Drive

Cycle.>

Is DTC P1451 displayed on the

display?

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

End.

15WRX_STI_US_EN.book 289 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-290

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DX:DTC P2004 INTAKE MANIFOLD RUNNER CONTROL STUCK OPEN (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-167, DTC P2004 INTAKE MANIFOLD RUNNER CONTROL

STUCK OPEN (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK TUMBLE GENERATOR VALVE RH.

1) Remove the tumble generator valve assem-

bly RH.

2) Check the tumble generator valve body.

Is there any dirt or clogging with

foreign objects in the tumble

generator valve?

Clean the tumble

generator valve.

Replace the tum-

ble generator valve

assembly RH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 290 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-291

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DY:DTC P2005 INTAKE MANIFOLD RUNNER CONTROL STUCK OPEN (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-168, DTC P2005 INTAKE MANIFOLD RUNNER CONTROL

STUCK OPEN (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK TUMBLE GENERATOR VALVE LH.

1) Remove the tumble generator valve assem-

bly LH.

2) Check the tumble generator valve body.

Is there any dirt or clogging with

foreign objects in the tumble

generator valve?

Clean the tumble

generator valve.

Replace the tum-

ble generator valve

assembly LH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 291 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-292

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DZ:DTC P2006 INTAKE MANIFOLD RUNNER CONTROL STUCK CLOSED

(BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-169, DTC P2006 INTAKE MANIFOLD RUNNER CONTROL

STUCK CLOSED (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK TUMBLE GENERATOR VALVE RH.

1) Remove the tumble generator valve assem-

bly RH.

2) Check the tumble generator valve body.

Is there any dirt or clogging with

foreign objects in the tumble

generator valve?

Clean the tumble

generator valve.

Replace the tum-

ble generator valve

assembly RH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 292 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-293

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EA:DTC P2007 INTAKE MANIFOLD RUNNER CONTROL STUCK CLOSED

(BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-170, DTC P2007 INTAKE MANIFOLD RUNNER CONTROL

STUCK CLOSED (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK TUMBLE GENERATOR VALVE LH.

1) Remove the tumble generator valve assem-

bly LH.

2) Check the tumble generator valve body.

Is there any dirt or clogging with

foreign objects in the tumble

generator valve?

Clean the tumble

generator valve.

Replace the tum-

ble generator valve

assembly LH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 293 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-294

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EB:DTC P2008 INTAKE MANIFOLD RUNNER CONTROL CIRCUIT / OPEN

(BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-171, DTC P2008 INTAKE MANIFOLD RUNNER CONTROL

CIRCUIT / OPEN (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 294 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-295

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from the ECM

and tumble generator valve assembly RH.

3) Measure the resistance of harness between

ECM connector and tumble generator valve

assembly RH connector.

Connector & terminal

(B134) No. 25 — (E55) No. 5:

(B134) No. 26 — (E55) No. 4:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 25 — Chassis ground:

(B134) No. 26 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector.

3 CHECK FOR POOR CONTACT.

Check for poor contact of tumble generator

valve assembly RH connector.

Is there poor contact of the tum-

ble generator valve assembly

RH connector?

Repair the poor

contact of tumble

generator valve

assembly RH con-

nector.

Replace the tum-

ble generator valve

assembly RH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 295 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-296

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EC:DTC P2009 INTAKE MANIFOLD RUNNER CONTROL CIRCUIT LOW (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-172, DTC P2009 INTAKE MANIFOLD RUNNER CONTROL

CIRCUIT LOW (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 296 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-297

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 25 (+) — Chassis ground (–):

(B134) No. 26 (+) — Chassis ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector.

Replace the tum-

ble generator valve

assembly RH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 297 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-298

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

ED:DTC P2011 INTAKE MANIFOLD RUNNER CONTROL CIRCUIT / OPEN

(BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-173, DTC P2011 INTAKE MANIFOLD RUNNER CONTROL

CIRCUIT / OPEN (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 298 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-299

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

tumble generator valve assembly LH.

3) Measure the resistance of harness between

ECM connector and tumble generator valve

assembly LH connector.

Connector & terminal

(B134) No. 23 — (E51) No. 5:

(B134) No. 24 — (E51) No. 4:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 23 — Chassis ground:

(B134) No. 24 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector.

3 CHECK FOR POOR CONTACT.

Check for poor contact of tumble generator

valve assembly LH connector.

Is there poor contact of the tum-

ble generator valve assembly

LH connector?

Repair the poor

contact of tumble

generator valve

assembly LH con-

nector.

Replace the tum-

ble generator valve

assembly LH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 299 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-300

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EE:DTC P2012 INTAKE MANIFOLD RUNNER CONTROL CIRCUIT LOW (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-174, DTC P2012 INTAKE MANIFOLD RUNNER CONTROL

CIRCUIT LOW (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 300 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-301

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 23 (+) — Chassis ground (–):

(B134) No. 24 (+) — Chassis ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector.

Replace the tum-

ble generator valve

assembly LH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 301 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-302

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EF:DTC P2016 TUMBLE GENERATED VALVE POSITION SENSOR 1 CIRCUIT

LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-175, DTC P2016 TUMBLE GENERATED VALVE POSITION

SENSOR 1 CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 302 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-303

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 303 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-304

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «TGV Position Sensor R»

using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «TGV Position

Sensor R» less than 0.2 V?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK POWER SUPPLY OF TUMBLE GEN-

ERATOR VALVE ASSEMBLY RH.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from tumble gen-

erator valve assembly RH.

3) Turn the ignition switch to ON.

4) Measure the voltage between tumble gener-

ator valve assembly RH connector and engine

ground.

Connector & terminal

(E55) No. 3 (+) — Engine ground (–):

Is the voltage 4.5 V or more? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and tumble generator valve

assembly RH connector.

Connector & terminal

(B137) No. 11 — (E55) No. 1:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 11 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector.

5 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and tumble gen-

erator valve assembly RH connector.

Is there poor contact of ECM or

the tumble generator valve

assembly RH connector?

Repair the poor

contact of ECM or

tumble generator

valve assembly RH

connector.

Replace the tum-

ble generator valve

assembly RH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 304 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-305

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EG:DTC P2017 TUMBLE GENERATED VALVE POSITION SENSOR 1 CIRCUIT

HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-176, DTC P2017 TUMBLE GENERATED VALVE POSITION

SENSOR 1 CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 305 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-306

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 306 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-307

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «TGV Position Sensor R»

using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «TGV Position

Sensor R» 5 V or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from tumble gen-

erator valve assembly RH.

3) Start the engine.

4) Read the value of «TGV Position Sensor R»

using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «TGV Position

Sensor R» 5 V or more?

Repair the short

circuit to power in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

RH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance of harness between

tumble generator valve assembly RH connector

and engine ground.

Connector & terminal

(E55) No. 2 — Engine ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly RH connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

4 CHECK FOR POOR CONTACT.

Check for poor contact of tumble generator

valve assembly RH connector.

Is there poor contact of the tum-

ble generator valve assembly

RH connector?

Repair the poor

contact of tumble

generator valve

assembly RH con-

nector.

Replace the tum-

ble generator valve

assembly RH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 307 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-308

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EH:DTC P2021 TUMBLE GENERATED VALVE POSITION SENSOR 2 CIRCUIT

LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-177, DTC P2021 TUMBLE GENERATED VALVE POSITION

SENSOR 2 CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 308 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-309

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 309 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-310

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «TGV Position Sensor L»

using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «TGV Position

Sensor L» less than 0.2 V?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK POWER SUPPLY OF TUMBLE GEN-

ERATOR VALVE ASSEMBLY LH.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from tumble gen-

erator valve assembly LH.

3) Turn the ignition switch to ON.

4) Measure the voltage between tumble gener-

ator valve assembly LH connector and engine

ground.

Connector & terminal

(E51) No. 3 (+) — Engine ground (–):

Is the voltage 4.5 V or more? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and tumble generator valve

assembly LH connector.

Connector & terminal

(B137) No. 10 — (E51) No. 1:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 10 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector.

5 CHECK FOR POOR CONTACT.

Check for poor contact of ECM and tumble gen-

erator valve assembly LH connector.

Is there poor contact of ECM or

the tumble generator valve

assembly LH connector?

Repair the poor

contact of ECM or

tumble generator

valve assembly LH

connector.

Replace the tum-

ble generator valve

assembly LH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 310 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-311

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EI: DTC P2022 TUMBLE GENERATED VALVE POSITION SENSOR 2 CIRCUIT

HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-178, DTC P2022 TUMBLE GENERATED VALVE POSITION

SENSOR 2 CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 311 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-312

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

5A25

4A26

EN-10873

E51

E55

213

B134A:

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E55

D11

A29

3A19

E51

D10

4A24

5A23

ECM

TUMBLE GENERATOR

VALVE ASSY LH

TUMBLE GENERATOR

VALVE ASSY RH

15WRX_STI_US_EN.book 312 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-313

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Start the engine.

2) Read the value of «TGV Position Sensor L»

using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «TGV Position

Sensor L» 5 V or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from tumble gen-

erator valve assembly LH.

3) Start the engine.

4) Read the value of «TGV Position Sensor L»

using the Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «TGV Position

Sensor L» 5 V or more?

Repair the short

circuit to power in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

TUMBLE GENERATOR VALVE ASSEMBLY

LH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance of harness between

tumble generator valve assembly LH connector

and engine ground.

Connector & terminal

(E51) No. 2 — Engine ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and tumble gener-

ator valve assem-

bly LH connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

4 CHECK FOR POOR CONTACT.

Check for poor contact of tumble generator

valve assembly LH connector.

Is there poor contact of the tum-

ble generator valve assembly

LH connector?

Repair the poor

contact of tumble

generator valve

assembly LH con-

nector.

Replace the tum-

ble generator valve

assembly LH.

<Ref. to FU(STI)-

46, Tumble Gener-

ator Valve Assem-

bly.>

15WRX_STI_US_EN.book 313 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-314

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EJ:DTC P2088 INTAKE CAMSHAFT POSITION ACTUATOR CONTROL CIRCUIT

LOW (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-179, DTC P2088 INTAKE CAMSHAFT POSITION ACTUA-

TOR CONTROL CIRCUIT LOW (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

E38E37

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E38

EN-10874

B134

E37

INTAKE OIL FLOW CONTROL

SOLENOID VALVE LH

INTAKE OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 314 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-315

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve RH.

3) Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve RH connector.

Connector & terminal

(B134) No. 34 — (E38) No. 1:

(B134) No. 27 — (E38) No. 2:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 34 — Chassis ground:

(B134) No. 27 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector.

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve RH

connector.

Replace the oil

flow control sole-

noid valve RH.

<Ref. to ME(STI)-

62, Camshaft.>

15WRX_STI_US_EN.book 315 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-316

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EK:DTC P2089 INTAKE CAMSHAFT POSITION ACTUATOR CONTROL CIRCUIT

HIGH (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-180, DTC P2089 INTAKE CAMSHAFT POSITION ACTUA-

TOR CONTROL CIRCUIT HIGH (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve RH.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 34 (+) — Chassis ground (–):

(B134) No. 27 (+) — Chassis ground (–):

Is the voltage less than 1 V? Go to step 2. Repair the short

circuit to power in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector.

ECM

E38E37

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E38

EN-10874

B134

E37

INTAKE OIL FLOW CONTROL

SOLENOID VALVE LH

INTAKE OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 316 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-317

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve RH connector.

Connector & terminal

(B134) No. 34 — (E38) No. 1:

(B134) No. 27 — (E38) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector

• Poor contact of

coupling connector

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve RH

connector.

Replace the oil

flow control sole-

noid valve RH.

<Ref. to ME(STI)-

62, Camshaft.>

Step Check Yes No

15WRX_STI_US_EN.book 317 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-318

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EL:DTC P2090 EXHAUST CAMSHAFT POSITION ACTUATOR CONTROL CIR-

CUIT LOW (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-181, DTC P2090 EXHAUST CAMSHAFT POSITION ACTU-

ATOR CONTROL CIRCUIT LOW (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

E66E63

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E63

EN-10875

B134

E66

ECM

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE LH

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 318 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-319

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve RH.

3) Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve RH connector.

Connector & terminal

(B134) No. 7 — (E63) No. 1:

(B134) No. 15 — (E63) No. 2:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 7 — Chassis ground:

(B134) No. 15 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector.

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve RH

connector.

Replace the oil

flow control sole-

noid valve RH.

<Ref. to FU(STI)-

48, Oil Flow Con-

trol Solenoid

Valve.>

15WRX_STI_US_EN.book 319 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-320

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EM:DTC P2091 EXHAUST CAMSHAFT POSITION ACTUATOR CONTROL CIR-

CUIT HIGH (BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-182, DTC P2091 EXHAUST CAMSHAFT POSITION ACTU-

ATOR CONTROL CIRCUIT HIGH (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve RH.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 7 (+) — Chassis ground (–):

(B134) No. 15 (+) — Chassis ground (–):

Is the voltage less than 1 V? Go to step 2. Repair the short

circuit to power in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector.

E66E63

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E63

EN-10875

B134

E66

ECM

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE LH

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 320 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-321

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE RH

CONNECTOR.

Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve RH connector.

Connector & terminal

(B134) No. 7 — (E63) No. 1:

(B134) No. 15 — (E63) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve RH

connector

• Poor contact of

coupling connector

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve RH

connector.

Replace the oil

flow control sole-

noid valve RH.

<Ref. to FU(STI)-

48, Oil Flow Con-

trol Solenoid

Valve.>

Step Check Yes No

15WRX_STI_US_EN.book 321 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-322

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EN:DTC P2092 INTAKE CAMSHAFT POSITION ACTUATOR CONTROL CIRCUIT

LOW (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-183, DTC P2092 INTAKE CAMSHAFT POSITION ACTUA-

TOR CONTROL CIRCUIT LOW (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

E38E37

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E38

EN-10874

B134

E37

INTAKE OIL FLOW CONTROL

SOLENOID VALVE LH

INTAKE OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 322 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-323

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve LH.

3) Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve LH connector.

Connector & terminal

(B134) No. 17 — (E37) No. 1:

(B134) No. 16 — (E37) No. 2:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 17 — Chassis ground:

(B134) No. 16 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector.

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve LH

connector.

Replace the oil

flow control sole-

noid valve LH.

<Ref. to ME(STI)-

62, Camshaft.>

15WRX_STI_US_EN.book 323 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-324

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EO:DTC P2093 INTAKE CAMSHAFT POSITION ACTUATOR CONTROL CIRCUIT

HIGH (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-183, DTC P2093 INTAKE CAMSHAFT POSITION ACTUA-

TOR CONTROL CIRCUIT HIGH (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve LH.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 17 (+) — Chassis ground (–):

(B134) No. 16 (+) — Chassis ground (–):

Is the voltage less than 1 V? Go to step 2. Repair the short

circuit to power in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector.

ECM

E38E37

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E38

EN-10874

B134

E37

INTAKE OIL FLOW CONTROL

SOLENOID VALVE LH

INTAKE OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 324 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-325

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve LH connector.

Connector & terminal

(B134) No. 17 — (E37) No. 1:

(B134) No. 16 — (E37) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector

• Poor contact of

coupling connector

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve LH

connector.

Replace the oil

flow control sole-

noid valve LH.

<Ref. to ME(STI)-

62, Camshaft.>

Step Check Yes No

15WRX_STI_US_EN.book 325 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-326

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EP:DTC P2094 EXHAUST CAMSHAFT POSITION ACTUATOR CONTROL CIR-

CUIT LOW (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-183, DTC P2094 EXHAUST CAMSHAFT POSITION ACTU-

ATOR CONTROL CIRCUIT LOW (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

E66E63

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E63

EN-10875

B134

E66

ECM

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE LH

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 326 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-327

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve LH.

3) Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve LH connector.

Connector & terminal

(B134) No. 5 — (E66) No. 1:

(B134) No. 14 — (E66) No. 2:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 5 — Chassis ground:

(B134) No. 14 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector.

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve LH

connector.

Replace the oil

flow control sole-

noid valve LH.

<Ref. to FU(STI)-

48, Oil Flow Con-

trol Solenoid

Valve.>

15WRX_STI_US_EN.book 327 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-328

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EQ:DTC P2095 EXHAUST CAMSHAFT POSITION ACTUATOR CONTROL CIR-

CUIT HIGH (BANK 2)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-183, DTC P2095 EXHAUST CAMSHAFT POSITION ACTU-

ATOR CONTROL CIRCUIT HIGH (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

oil flow control solenoid valve LH.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 5 (+) — Chassis ground (–):

(B134) No. 14 (+) — Chassis ground (–):

Is the voltage less than 1 V? Go to step 2. Repair the short

circuit to power in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector.

E66E63

2719 20 21 22

28 29 3332 3430 31

1413121110

1234567

B134

16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

78563412

34 35 36 37 38 39 40 41

42 43 44 45 46 47

48 49 50 51 52 53 54

B21

E2B21

E63

EN-10875

B134

E66

ECM

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE LH

EXHAUST OIL FLOW CONTROL

SOLENOID VALVE RH

15WRX_STI_US_EN.book 328 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-329

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK HARNESS BETWEEN ECM AND OIL

FLOW CONTROL SOLENOID VALVE LH

CONNECTOR.

Measure the resistance of harness between

ECM connector and oil flow control solenoid

valve LH connector.

Connector & terminal

(B134) No. 5 — (E66) No. 1:

(B134) No. 14 — (E66) No. 2:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and oil flow control

solenoid valve LH

connector

• Poor contact of

coupling connector

3 CHECK OIL FLOW CONTROL SOLENOID

VALVE.

Measure the resistance between oil flow control

solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 6 — 12 Ω? Repair the poor

contact of ECM

and oil flow control

solenoid valve LH

connector.

Replace the oil

flow control sole-

noid valve LH.

<Ref. to FU(STI)-

48, Oil Flow Con-

trol Solenoid

Valve.>

Step Check Yes No

15WRX_STI_US_EN.book 329 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-330

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

ER:DTC P2096 POST CATALYST FUEL TRIM SYSTEM TOO LEAN (BANK 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-184, DTC P2096 POST CATALYST FUEL TRIM SYSTEM

TOO LEAN (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 330 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-331

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check DTC using

“List of Diagnostic

Trouble Code

(DTC)”. <Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 3.

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 331 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-332

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

3 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

3) Measure the resistance of harness between

ECM connector and front oxygen (A/F) sensor

connector.

Connector & terminal

(B136) No. 18 — (B379) No. 3:

(B136) No. 19 — (B379) No. 4:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector

• Poor contact of

front oxygen (A/F)

sensor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 18 — Chassis ground:

(B136) No. 19 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector.

5 CHECK OUTPUT SIGNAL FOR ECM.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between front oxygen

(A/F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 4 (+) — Chassis ground (–):

Is the voltage 4.5 V or more? Go to step 7. Go to step 6.

6 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between front oxygen (A/

F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 3 (+) — Chassis ground (–):

Is the voltage 4.95 V or more? Go to step 7. Go to step 8.

7 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between front oxygen (A/

F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 3 (+) — Chassis ground (–):

(B379) No. 4 (+) — Chassis ground (–):

Is the voltage 8 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

After repair,

replace the ECM.

<Ref. to FU(STI)-

56, Engine Control

Module (ECM).>

Repair the poor

contact of ECM

connector.

8 CHECK EXHAUST SYSTEM. Are there holes or loose bolts

on exhaust system?

Repair the exhaust

system.

Go to step 9.

9 CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or

disconnection of hose on air

intake system?

Repair the air

intake system.

Go to step 10

Step Check Yes No

15WRX_STI_US_EN.book 332 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-333

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

10 CHECK FUEL PRESSURE.

WARNING:

Place “NO OPEN FLAMES” signs near the

working area.

CAUTION:

Be careful not to spill fuel.

1) Connect the front oxygen (A/F) sensor con-

nector.

2) Measure the fuel pressure while discon-

necting pressure regulator vacuum hose from

intake manifold. <Ref. to ME(STI)-25, INSPEC-

TION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

If fuel pressure does not increase, squeeze the

fuel return hose 2 to 3 times, then measure fuel

pressure again.

Is the measured value 284 —

314 kPa (2.9 — 3.2 kgf/cm

, 41

— 46 psi)?

Go to step 11. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

11 CHECK FUEL PRESSURE.

After connecting the pressure regulator vacuum

hose, measure fuel pressure. <Ref. to ME(STI)-

25, INSPECTION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

• If fuel pressure does not increase, squeeze

fuel return hose 2 to 3 times, then measure fuel

pressure again.

• If the measured value at this step is out of

specification, check or replace pressure regula-

tor and pressure regulator vacuum hose.

Is the measured value 230 —

260 kPa (2.4 — 2.7 kgf/cm

, 33

— 38 psi)?

Go to step 12. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

12 CHECK ENGINE COOLANT TEMPERATURE

SENSOR.

1) Start the engine and warm up completely.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

75°C (167°F) or more?

Go to step 13. Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

Step Check Yes No

15WRX_STI_US_EN.book 333 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-334

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

13 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Read the value of «Mass Air Flow» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mass Air

Flow» 2.0 — 5.0 g/s (0.26 —

0.66 lb/m)?

Go to step 14. Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

14 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Open the front hood.

6) Measure the ambient temperature.

7) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Subtract ambient temperature

from «Intake Air Temp.». Is the

obtained value –10 — 50°C (–18

— 90°F)?

Go to step 15. Check the mass air

flow and intake air

temperature sen-

sor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

keep the engine speed at 3,000 rpm. (2 minutes

maximum)

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Depress the clutch pedal.

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.490 V or more?

Go to step 16. Go to step 17.

Step Check Yes No

15WRX_STI_US_EN.book 334 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-335

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

16 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

rapidly reduce the engine speed from 3,000

rpm.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Depress the clutch pedal.

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.250 V or less?

Go to step 18. Go to step 17.

17 CHECK REAR OXYGEN SENSOR CONNEC-

TOR AND COUPLING CONNECTOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 19.

18 CHECK FRONT OXYGEN (A/F) SENSOR US-

ING REAR OXYGEN SENSOR SIGNAL.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), then

keep the engine idling for 5 minutes or more.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value in «Rear O2 Sen-

sor» kept at 0.250 V or less for 5

minutes or more?

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

Go to step 19.

19 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 20. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 335 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-336

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

20 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 (+) — Chassis ground (–):

Is the voltage 0.2 — 0.5 V? Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 336 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-337

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

ES:DTC P2097 POST CATALYST FUEL TRIM SYSTEM TOO RICH (BANK 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-185, DTC P2097 POST CATALYST FUEL TRIM SYSTEM

TOO RICH (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 337 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-338

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check DTC using

“List of Diagnostic

Trouble Code

(DTC)”. <Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 3.

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 338 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-339

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

3 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

3) Measure the resistance of harness between

ECM connector and front oxygen (A/F) sensor

connector.

Connector & terminal

(B136) No. 18 — (B379) No. 3:

(B136) No. 19 — (B379) No. 4:

Is the resistance less than 1 Ω? Go to step 4. Repair the open

circuit of harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

4 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 18 — Chassis ground:

(B136) No. 19 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector.

5 CHECK OUTPUT SIGNAL FOR ECM.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between front oxygen

(A/F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 4 (+) — Chassis ground (–):

Is the voltage 4.5 V or more? Go to step 7. Go to step 6.

6 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between front oxygen (A/

F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 3 (+) — Chassis ground (–):

Is the voltage 4.95 V or more? Go to step 7. Go to step 8.

7 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between front oxygen (A/

F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 3 (+) — Chassis ground (–):

(B379) No. 4 (+) — Chassis ground (–):

Is the voltage 8 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

After repair,

replace the ECM.

<Ref. to FU(STI)-

56, Engine Control

Module (ECM).>

Repair the poor

contact of ECM

connector.

8 CHECK EXHAUST SYSTEM. Are there holes or loose bolts

on exhaust system?

Repair the exhaust

system.

Go to step 9.

9 CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or

disconnection of hose on air

intake system?

Repair the air

intake system.

Go to step 10.

Step Check Yes No

15WRX_STI_US_EN.book 339 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-340

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

10 CHECK FUEL PRESSURE.

WARNING:

Place “NO OPEN FLAMES” signs near the

working area.

CAUTION:

Be careful not to spill fuel.

1) Connect the front oxygen (A/F) sensor con-

nector.

2) Measure the fuel pressure while discon-

necting pressure regulator vacuum hose from

intake manifold. <Ref. to ME(STI)-25, INSPEC-

TION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

If fuel pressure does not increase, squeeze the

fuel return hose 2 to 3 times, then measure fuel

pressure again.

Is the measured value 284 —

314 kPa (2.9 — 3.2 kgf/cm

, 41

— 46 psi)?

Go to step 11. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

11 CHECK FUEL PRESSURE.

After connecting the pressure regulator vacuum

hose, measure fuel pressure. <Ref. to ME(STI)-

25, INSPECTION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

• If fuel pressure does not increase, squeeze

fuel return hose 2 to 3 times, then measure fuel

pressure again.

• If the measured value at this step is out of

specification, check or replace pressure regula-

tor and pressure regulator vacuum hose.

Is the measured value 230 —

260 kPa (2.4 — 2.7 kgf/cm

, 33

— 38 psi)?

Go to step 12. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

12 CHECK ENGINE COOLANT TEMPERATURE

SENSOR.

1) Start the engine and warm up completely.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

75°C (167°F) or more?

Go to step 13. Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

Step Check Yes No

15WRX_STI_US_EN.book 340 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-341

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

13 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Read the value of «Mass Air Flow» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mass Air

Flow» 2.0 — 5.0 g/s (0.26 —

0.66 lb/m)?

Go to step 14. Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

14 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Open the front hood.

6) Measure the ambient temperature.

7) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Subtract ambient temperature

from «Intake Air Temp.». Is the

obtained value –10 — 50°C (–18

— 90°F)?

Go to step 15. Check the mass air

flow and intake air

temperature sen-

sor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

15 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

keep the engine speed at 3,000 rpm. (2 minutes

maximum)

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Depress the clutch pedal.

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.490 V or more?

Go to step 16. Go to step 17.

Step Check Yes No

15WRX_STI_US_EN.book 341 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-342

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

16 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

rapidly reduce the engine speed from 3,000

rpm.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Depress the clutch pedal.

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.250 V or less?

Go to step 18. Go to step 17.

17 CHECK REAR OXYGEN SENSOR CONNEC-

TOR AND COUPLING CONNECTOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 19.

18 CHECK FRONT OXYGEN (A/F) SENSOR US-

ING REAR OXYGEN SENSOR SIGNAL.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), then

keep the engine idling for 5 minutes or more.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value in «Rear O2 Sen-

sor» kept at 0.8 V or more for 5

minutes or more?

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

Go to step 19.

19 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 20. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 342 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-343

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

20 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 (+) — Chassis ground (–):

Is the voltage 0.2 — 0.5 V? Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 343 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-344

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

ET:DTC P2101 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT RANGE/

PERFORMANCE

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-186, DTC P2101 THROTTLE ACTUATOR CONTROL MO-

TOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 344 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-345

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Step Check Yes No

1 CHECK ELECTRONIC THROTTLE CON-

TROL RELAY.

1) Turn the ignition switch to OFF.

2) Remove the electronic throttle control relay.

3) Connect the battery to terminals No. 16 and

No. 17 of electronic throttle control relay.

4) Measure the resistance between electronic

throttle control relay terminals.

Terminals

No. 14 — No. 15:

Is the resistance less than 1 Ω? Go to step 2. Replace the elec-

tronic throttle con-

trol relay. <Ref. to

FU(STI)-60, Elec-

tronic Throttle

Control Relay.>

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 345 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-346

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

2 CHECK POWER SUPPLY OF ELECTRONIC

THROTTLE CONTROL RELAY.

Measure the voltage between electronic throttle

control relay connector and chassis ground.

Connector & terminal

(B225) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 3. Repair the open or

ground short circuit

of power supply

circuit.

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Disconnect the connector from ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 17 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 14 — Chassis ground:

(B225) No. 17 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and electronic

throttle control

relay connector.

5 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

Measure the resistance between ECM connec-

tor and electronic throttle control relay connec-

tor.

Connector & terminal

(B135) No. 7 — (B225) No. 14:

(B135) No. 17 — (B225) No. 17:

Is the resistance less than 1 Ω? Go to step 6. Repair the open

circuit in harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

6 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from electronic

throttle control.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 19 — Chassis ground:

(B134) No. 18 — Chassis ground:

(B134) No. 18 — (B136) No. 4:

(B134) No. 28 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 7. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

7 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 6 — Engine ground:

(E57) No. 4 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 8. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

Step Check Yes No

15WRX_STI_US_EN.book 346 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-347

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

8 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between

ECM connector and electronic throttle control

connector.

Connector & terminal

(B134) No. 18 — (E57) No. 6:

(B134) No. 28 — (E57) No. 4:

(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 Ω? Go to step 9. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

9 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step 10. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

10 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 4 (+) — Engine ground (–):

(E57) No. 6 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 11.

11 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B134) No. 19 — (B134) No. 18:

(B134) No. 19 — (B134) No. 28:

Is the resistance 1 MΩ or

more?

Go to step 12. Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

12 CHECK SENSOR OUTPUT.

1) Connect all connectors.

2) Start the engine and warm up completely.

3) Stop the engine, and then turn the ignition

switch to ON (engine OFF).

4) Read the value of «Main-Throttle Sensor»

using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Main-Throttle

Sensor» 0.81 — 0.87 V?

Go to step 13. Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

Step Check Yes No

15WRX_STI_US_EN.book 347 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-348

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

13 CHECK SENSOR OUTPUT.

Read the value of «Sub-Throttle Sensor» using

Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Sub-Throttle

Sensor» 1.64 — 1.70 V?

Go to step 14. Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

14 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL MO-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance between ECM con-

nector and electronic throttle control connector.

Connector & terminal

(B134) No. 1 — (E57) No. 1:

(B134) No. 2 — (E57) No. 2:

Is the resistance less than 1 Ω? Go to step 15. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

15 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL MO-

TOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 1 (+) — Engine ground (–):

(E57) No. 2 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 16.

16 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL MO-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 1 — Engine ground:

(E57) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 17. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

17 CHECK ELECTRONIC THROTTLE CON-

TROL MOTOR HARNESS.

Measure the resistance between electronic

throttle control connectors.

Connector & terminal

(E57) No. 1 — (E57) No. 2:

Is the resistance 1 MΩ or

more?

Go to step 18. Repair the short

circuit in harness

between ECM con-

nector and elec-

tronic throttle

control connector.

18 CHECK ELECTRONIC THROTTLE CON-

TROL GROUND CIRCUIT.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:

(B134) No. 4 — Chassis ground:

(B134) No. 6 — Chassis ground:

(B137) No. 1 — Chassis ground:

(B137) No. 3 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 19. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 348 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-349

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

19 CHECK ELECTRONIC THROTTLE CON-

TROL.

Measure the resistance between electronic

throttle control terminals.

Terminals

No. 1 — No. 2:

Is the resistance 50 Ω or less? Go to step 20. Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

20 CHECK ELECTRONIC THROTTLE CON-

TROL.

Move the throttle valve to the fully open and fully

closed positions with fingers.

Check that the valve returns to the specified

position when releasing fingers.

Does the valve return to the

specified position? Standard

value: 3 mm (0.12 in) from fully

closed position

Repair the poor

contact of ECM

connector.

Replace the elec-

tronic throttle con-

trol. <Ref. to

FU(STI)-15, Throt-

tle Body.>

Step Check Yes No

15WRX_STI_US_EN.book 349 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-350

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EU:DTC P2102 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-187, DTC P2102 THROTTLE ACTUATOR CONTROL MO-

TOR CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 350 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-351

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK ELECTRONIC THROTTLE CON-

TROL RELAY.

1) Turn the ignition switch to OFF.

2) Remove the electronic throttle control relay.

3) Connect the battery to terminals No. 16 and

No. 17 of electronic throttle control relay.

4) Measure the resistance between electronic

throttle control relay terminals.

Terminals

No. 14 — No. 15:

Is the resistance less than 1 Ω? Go to step 2. Replace the elec-

tronic throttle con-

trol relay. <Ref. to

FU(STI)-60, Elec-

tronic Throttle

Control Relay.>

2 CHECK POWER SUPPLY OF ELECTRONIC

THROTTLE CONTROL RELAY.

Measure the voltage between electronic throttle

control relay connector and chassis ground.

Connector & terminal

(B225) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 3. Repair the open or

ground short circuit

of power supply

circuit.

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Disconnect the connector from ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 17 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 14 — Chassis ground:

(B225) No. 17 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and electronic

throttle control

relay connector.

5 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

Measure the resistance between ECM connec-

tor and electronic throttle control relay connec-

tor.

Connector & terminal

(B135) No. 7 — (B225) No. 14:

(B135) No. 17 — (B225) No. 17:

Is the resistance less than 1 Ω? Repair the poor

contact of ECM

connector.

Repair the open

circuit in harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

15WRX_STI_US_EN.book 351 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-352

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EV:DTC P2103 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-188, DTC P2103 THROTTLE ACTUATOR CONTROL MO-

TOR CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 352 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-353

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EW:DTC P2109 THROTTLE/PEDAL POSITION SENSOR “A” MINIMUM STOP

PERFORMANCE

NOTE:

For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(STI)(diag)-344, DTC P2101 THROTTLE AC-

TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic

Trouble Code (DTC).>

EX:DTC P2119 THROTTLE ACTUATOR CONTROL THROTTLE BODY RANGE/

PERFORMANCE

NOTE:

For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(STI)(diag)-344, DTC P2101 THROTTLE AC-

TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic

Trouble Code (DTC).>

Step Check Yes No

1 CHECK ELECTRONIC THROTTLE CON-

TROL RELAY.

1) Turn the ignition switch to OFF.

2) Remove the electronic throttle control relay.

3) Measure the resistance between electronic

throttle control relay terminals.

Terminals

No. 14 — No. 15:

Is the resistance 1 MΩ or

more?

Go to step 2. Replace the elec-

tronic throttle con-

trol relay. <Ref. to

FU(STI)-60, Elec-

tronic Throttle

Control Relay.>

2 CHECK SHORT CIRCUIT OF ELECTRONIC

THROTTLE CONTROL RELAY POWER SUP-

PLY.

1) Turn the ignition switch to ON.

2) Measure the voltage between electronic

throttle control relay connector and chassis

ground.

Connector & terminal

(B225) No. 14 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control relay con-

nector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL RE-

LAY CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B135) No. 17 — Chassis ground:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of ECM

connector.

Repair the short

circuit to ground in

harness between

ECM connector

and electronic

throttle control

relay connector.

15WRX_STI_US_EN.book 353 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-354

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EY:DTC P2122 THROTTLE/PEDAL POSITION SENSOR/SWITCH “D” CIRCUIT

LOW INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-193, DTC P2122 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “D” CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B21

B83

456

123

B122

J/C

B134A:

B135B:

B136C:

B137D:

B122

56341

B315

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B315

B23

B29

B21

B31

B30

B22

B83

J/C

EN-10876

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

ACCELERATOR PEDAL

POSITION SENSOR

15WRX_STI_US_EN.book 354 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-355

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

accelerator pedal position sensor.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B135) No. 21 — Chassis ground:

(B135) No. 23 — Chassis ground:

(B135) No. 23 — (B136) No. 4:

Is the resistance 1 MΩ or

more?

Go to step 2. Repair the short

circuit to ground in

harness between

ECM connector

and accelerator

pedal position sen-

sor connector.

2 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between accelera-

tor pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 6 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the accel-

erator pedal. <Ref.

to SP(STI)-4,

Accelerator

Pedal.>

Repair the short

circuit to ground in

harness between

ECM connector

and accelerator

pedal position sen-

sor connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

15WRX_STI_US_EN.book 355 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-356

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EZ:DTC P2123 THROTTLE/PEDAL POSITION SENSOR/SWITCH “D” CIRCUIT

HIGH INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-194, DTC P2123 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “D” CIRCUIT HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B21

B83

456

123

B122

J/C

B134A:

B135B:

B136C:

B137D:

B122

56341

B315

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B315

B23

B29

B21

B31

B30

B22

B83

J/C

EN-10876

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

ACCELERATOR PEDAL

POSITION SENSOR

15WRX_STI_US_EN.book 356 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-357

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

accelerator pedal position sensor.

3) Measure the resistance of harness between

ECM connector and accelerator pedal position

sensor connector.

Connector & terminal

(B135) No. 23 — (B315) No. 6:

(B135) No. 29 — (B315) No. 5:

Is the resistance less than 1 Ω? Go to step 2. Repair the open

circuit of harness

between ECM con-

nector and accel-

erator pedal

position sensor

connector.

2 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between accelera-

tor pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 5 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between accelerator

pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 6 (+) — Chassis ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power

supply in harness

between ECM con-

nector and accel-

erator pedal

position sensor

connector.

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B135) No. 21 — (B135) No. 23:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of acceler-

ator pedal position

sensor connector.

Replace the accel-

erator pedal if

defective. <Ref. to

SP(STI)-4, Accel-

erator Pedal.>

Repair the short

circuit to power

supply in harness

between ECM con-

nector and accel-

erator pedal

position sensor

connector.

15WRX_STI_US_EN.book 357 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-358

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FA:DTC P2127 THROTTLE/PEDAL POSITION SENSOR/SWITCH “E” CIRCUIT

LOW INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-195, DTC P2127 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “E” CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B21

B83

456

123

B122

J/C

B134A:

B135B:

B136C:

B137D:

B122

56341

B315

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B315

B23

B29

B21

B31

B30

B22

B83

J/C

EN-10876

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

ACCELERATOR PEDAL

POSITION SENSOR

15WRX_STI_US_EN.book 358 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-359

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

accelerator pedal position sensor.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B135) No. 22 — Chassis ground:

(B135) No. 31 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 2. Repair the short

circuit to ground in

harness between

ECM connector

and accelerator

pedal position sen-

sor connector.

2 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between accelera-

tor pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 3 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the accel-

erator pedal. <Ref.

to SP(STI)-4,

Accelerator

Pedal.>

Repair the short

circuit to ground in

harness between

ECM connector

and accelerator

pedal position sen-

sor connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

15WRX_STI_US_EN.book 359 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-360

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FB:DTC P2128 THROTTLE/PEDAL POSITION SENSOR/SWITCH “E” CIRCUIT

HIGH INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-196, DTC P2128 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “E” CIRCUIT HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B21

B83

456

123

B122

J/C

B134A:

B135B:

B136C:

B137D:

B122

56341

B315

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B315

B23

B29

B21

B31

B30

B22

B83

J/C

EN-10876

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

ACCELERATOR PEDAL

POSITION SENSOR

15WRX_STI_US_EN.book 360 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-361

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

accelerator pedal position sensor.

3) Measure the resistance of harness between

ECM connector and accelerator pedal position

sensor connector.

Connector & terminal

(B135) No. 31 — (B315) No. 3:

(B135) No. 30 — (B315) No. 2:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and accelerator

pedal position sen-

sor connector

• Poor contact of

joint connector

2 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between accelera-

tor pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 2 — Chassis ground:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between accelerator

pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 3 (+) — Chassis ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power

supply in harness

between ECM con-

nector and accel-

erator pedal

position sensor

connector.

Go to step 4.

4 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B135) No. 22 — (B135) No. 31:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of acceler-

ator pedal position

sensor connector.

Replace the accel-

erator pedal if

defective. <Ref. to

SP(STI)-4, Accel-

erator Pedal.>

Repair the short

circuit to power

supply in harness

between ECM con-

nector and accel-

erator pedal

position sensor

connector.

15WRX_STI_US_EN.book 361 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-362

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FC:DTC P2135 THROTTLE/PEDAL POSITION SENSOR/SWITCH “A”/“B” VOLT-

AGE CORRELATION

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-197, DTC P2135 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “A”/“B” VOLTAGE CORRELATION, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B225

B122

J/C

B550

216

418

B220

1011

B21

E57

B134A:

B135B:

B136C:

B137D:

A29

A28

A19

A18

B17

B225B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

321654

E57

B122

EN-10861

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

ECM

SBF-7

101

242322 272625212019

432

698

11 12

B550

BATTERY

: TERMINAL No. OPTIONAL ARRANGEMENT

ELECTRONIC THROTTLE

CONTROL

MAIN

RELAY

FUSE

HOLDER

ELECTRONIC THROTTLE

CONTROL RELAY

15WRX_STI_US_EN.book 362 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-363

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

electronic throttle control.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B134) No. 19 — Chassis ground:

(B134) No. 18 — Chassis ground:

(B134) No. 18 — (B136) No. 4:

(B134) No. 28 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 2. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

2 CHECK SHORT CIRCUIT INSIDE THE ECM.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 4 — Engine ground:

(E57) No. 6 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the ground

short circuit of har-

ness between

ECM connector

and electronic

throttle control

connector.

Replace the ECM if

defective. <Ref. to

FU(STI)-56,

Engine Control

Module (ECM).>

3 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between

ECM connector and electronic throttle control

connector.

Connector & terminal

(B134) No. 18 — (E57) No. 6:

(B134) No. 28 — (E57) No. 4:

(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and electronic

throttle control

connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Connect the connector to ECM.

2) Measure the resistance between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step 5. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

5 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between electronic

throttle control connector and engine ground.

Connector & terminal

(E57) No. 4 (+) — Engine ground (–):

(E57) No. 6 (+) — Engine ground (–):

Is the voltage 5 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Go to step 6.

15WRX_STI_US_EN.book 363 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-364

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK HARNESS BETWEEN ECM AND

ELECTRONIC THROTTLE CONTROL CON-

NECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nectors.

Connector & terminal

(B134) No. 19 — (B134) No. 18:

(B134) No. 19 — (B134) No. 28:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of elec-

tronic throttle con-

trol connector.

Replace the elec-

tronic throttle con-

trol if defective.

<Ref. to FU(STI)-

15, Throttle Body.>

Repair the short

circuit to power in

the harness

between ECM con-

nector and elec-

tronic throttle

control connector.

Step Check Yes No

15WRX_STI_US_EN.book 364 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-365

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FD:DTC P2138 THROTTLE/PEDAL POSITION SENSOR/SWITCH “D”/“E” VOLT-

AGE CORRELATION

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-199, DTC P2138 THROTTLE/PEDAL POSITION SENSOR/

SWITCH “D”/“E” VOLTAGE CORRELATION, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B21

B83

456

123

B122

J/C

B134A:

B135B:

B136C:

B137D:

B122

56341

B315

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B315

B23

B29

B21

B31

B30

B22

B83

J/C

EN-10876

ECM

: TERMINAL No. OPTIONAL ARRANGEMENT

ACCELERATOR PEDAL

POSITION SENSOR

15WRX_STI_US_EN.book 365 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-366

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK ACCELERATOR PEDAL POSITION

SENSOR OUTPUT.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

Main accelerator pedal position sensor

signal

(B135) No. 23 (+) — Chassis ground (–):

Sub accelerator pedal position sensor

signal

(B135) No. 31 (+) — Chassis ground (–):

Is the difference in measured

values for the main accelerator

pedal position sensor signal

and the sub accelerator pedal

position sensor signal 0 V?

Go to step 3. Go to step 2.

2 CHECK ACCELERATOR PEDAL POSITION

SENSOR OUTPUT.

1) Measure the voltage between accelerator

pedal position sensor connector and chassis

ground.

Connector & terminal

(B315) No. 6 (+) — Chassis ground (–):

(B315) No. 3 (+) — Chassis ground (–):

Is the difference in measured

values for the main accelerator

pedal position sensor signal

and the sub accelerator pedal

position sensor signal 0 V?

Replace the accel-

erator pedal. <Ref.

to SP(STI)-4,

Accelerator

Pedal.>

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and accelerator

pedal position sen-

sor connector

• Short circuit to

ground in harness

between ECM con-

nector and accel-

erator pedal

position sensor

connector

3 CHECK HARNESS BETWEEN ECM AND AC-

CELERATOR PEDAL POSITION SENSOR

CONNECTOR.

Measure the resistance of harness between

accelerator pedal position sensor connector

and chassis ground.

Connector & terminal

(B315) No. 5 — Chassis ground:

(B315) No. 2 — Chassis ground:

Is the resistance less than 5 Ω? Repair the poor

contact of ECM

connector.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit of

harness between

ECM connector

and accelerator

pedal position sen-

sor connector

• Open circuit of

harness between

ECM connector

and engine ground

• Poor contact of

ECM connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 366 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-367

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FE:DTC P2158 VEHICLE SPEED SENSOR "B"

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-201, DTC P2158 VEHICLE SPEED SENSOR "B", Diagnos-

tic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK DTC OF VDC.

Check DTC of VDC.

Is DTC of VDC displayed? Perform the diag-

nosis according to

DTC. <Ref. to

VDC(diag)-42, List

of Diagnostic Trou-

ble Code (DTC).>

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 367 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-368

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FF:DTC P2195 O2 SENSOR SIGNAL BIASED/STUCK LEAN (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-202, DTC P2195 O2 SENSOR SIGNAL BIASED/STUCK

LEAN (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 368 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-369

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

3) Measure the resistance of harness between

ECM connector and front oxygen (A/F) sensor

connector.

Connector & terminal

(B136) No. 18 — (B379) No. 3:

(B136) No. 19 — (B379) No. 4:

Is the resistance less than 1 Ω? Go to step 3. Repair the open

circuit of harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

3 CHECK FOR POOR CONTACT.

Check for poor contact of the front oxygen (A/F)

sensor connector.

Is there poor contact of front

oxygen (A/F) sensor connec-

tor?

Repair the poor

contact of front

oxygen (A/F) sen-

sor connector.

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

15WRX_STI_US_EN.book 369 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-370

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FG:DTC P2196 O2 SENSOR SIGNAL BIASED/STUCK RICH (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-204, DTC P2196 O2 SENSOR SIGNAL BIASED/STUCK

RICH (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 370 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-371

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance between ECM con-

nector and chassis ground.

Connector & terminal

(B136) No. 18 — Chassis ground:

(B136) No. 19 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector.

3 CHECK OUTPUT SIGNAL FOR ECM.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 19 (+) — Chassis ground (–):

Is the voltage 4.5 V or more? Go to step 5. Go to step 4.

4 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between ECM connector

and chassis ground.

Connector & terminal

(B136) No. 18 (+) — Chassis ground (–):

Is the voltage 4.95 V or more? Go to step 5. Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

5 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between ECM connector

and chassis ground.

Connector & terminal

(B136) No. 18 (+) — Chassis ground (–):

(B136) No. 19 (+) — Chassis ground (–):

Is the voltage 8 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

After repair,

replace the ECM.

<Ref. to FU(STI)-

56, Engine Control

Module (ECM).>

Repair the poor

contact of ECM

connector.

15WRX_STI_US_EN.book 371 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-372

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FH:DTC P219A BANK 1 AIR-FUEL RATIO IMBALANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-206, DTC P219A BANK 1 AIR-FUEL RATIO IMBALANCE,

Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

456

123

B379

J/C

B379

B550

519

B225

B134A:

B136C:

B137D:

C19

C18

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10857

B21

SBF-5

ECM

101

242322 272625212019

432

698

11 12

B550

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

FRONT OXYGEN (A/F)

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 372 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-373

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 373 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-374

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FRONT OXYGEN (A/F) SENSOR

CONNECTOR AND COUPLING CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and

front oxygen (A/F) sensor.

3) Measure the resistance of harness between

ECM connector and front oxygen (A/F) sensor

connector.

Connector & terminal

(B136) No. 18 — (B379) No. 3:

(B136) No. 19 — (B379) No. 4:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector

• Poor contact of

coupling connector

B220

B550

216

B21

B134

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B134

10 11 12 13 14 15

72134

19 20 22

28 29

18 2521 23 24

3231

26 27

33 34

EN-10855

E16

E17

E16

E17

101

242322 272625212019

432

698

11 12

B550

SBF-7

ECM

FUEL INJECTOR No. 4

FUEL INJECTOR No. 3

FUEL INJECTOR No. 2

FUEL INJECTOR No. 1

BATTERY

FUSE HOLDER

MAIN RELAY

15WRX_STI_US_EN.book 374 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-375

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

3 CHECK HARNESS BETWEEN ECM AND

FRONT OXYGEN (A/F) SENSOR CONNEC-

TOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 18 — Chassis ground:

(B136) No. 19 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair the short

circuit to ground in

harness between

ECM connector

and front oxygen

(A/F) sensor con-

nector.

4 CHECK OUTPUT SIGNAL FOR ECM.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between front oxygen

(A/F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 4 (+) — Chassis ground (–):

Is the voltage 4.5 V or more? Go to step 6. Go to step 5.

5 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between front oxygen (A/

F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 3 (+) — Chassis ground (–):

Is the voltage 4.95 V or more? Go to step 6. Go to step 7.

6 CHECK OUTPUT SIGNAL FOR ECM.

Measure the voltage between front oxygen (A/

F) sensor connector and chassis ground.

Connector & terminal

(B379) No. 3 (+) — Chassis ground (–):

(B379) No. 4 (+) — Chassis ground (–):

Is the voltage 8 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and front

oxygen (A/F) sen-

sor connector.

After repair,

replace the ECM.

<Ref. to FU(STI)-

56, Engine Control

Module (ECM).>

Repair the poor

contact of ECM

connector.

7 CHECK EXHAUST SYSTEM. Are there holes or loose bolts

on exhaust system?

Repair the exhaust

system.

Go to step 8.

8 CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or

disconnection of hose on air

intake system?

Repair the air

intake system.

Go to step 9.

9 CHECK FUEL PRESSURE.

WARNING:

Place “NO OPEN FLAMES” signs near the

working area.

CAUTION:

Be careful not to spill fuel.

1) Connect the front oxygen (A/F) sensor con-

nector.

2) Measure the fuel pressure while discon-

necting pressure regulator vacuum hose from

intake manifold. <Ref. to ME(STI)-25, INSPEC-

TION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

If fuel pressure does not increase, squeeze the

fuel return hose 2 to 3 times, then measure fuel

pressure again.

Is the measured value 284 —

314 kPa (2.9 — 3.2 kg/cm

, 41

— 46 psi)?

Go to step 10. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

Step Check Yes No

15WRX_STI_US_EN.book 375 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-376

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

10 CHECK FUEL PRESSURE.

After connecting the pressure regulator vacuum

hose, measure fuel pressure. <Ref. to ME(STI)-

25, INSPECTION, Fuel Pressure.>

CAUTION:

Release fuel pressure before removing the

fuel pressure gauge.

NOTE:

• If fuel pressure does not increase, squeeze

fuel return hose 2 to 3 times, then measure fuel

pressure again.

• If the measured value at this step is out of

specification, check or replace pressure regula-

tor vacuum hose.

Is the measured value 230 —

260 kPa (2.4 — 2.7 kg/cm

, 33

— 38 psi)?

Go to step 11. Check the fuel

pump and fuel

delivery line. <Ref.

to FU(STI)-83,

INSPECTION,

Fuel Pump.> <Ref.

to FU(STI)-99,

INSPECTION,

Fuel Delivery,

Return and Evapo-

ration Lines.>

11 CHECK ENGINE COOLANT TEMPERATURE

SENSOR.

1) Start the engine and warm up completely.

2) Read the value of «Coolant Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Coolant Temp.»

75°C (167°F) or more?

Go to step 12. Replace the

engine coolant

temperature sen-

sor. <Ref. to

FU(STI)-33,

Engine Coolant

Temperature Sen-

sor.>

12 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Read the value of «Mass Air Flow» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Mass Air

Flow» 2.0 — 5.0 g/s (0.26 —

0.66 lb/m)?

Go to step 13. Replace the mass

air flow and intake

air temperature

sensor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

Step Check Yes No

15WRX_STI_US_EN.book 376 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-377

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

13 CHECK MASS AIR FLOW AND INTAKE AIR

TEMPERATURE SENSOR.

1) Start the engine and warm up engine until

coolant temperature is higher than 75°C

(167°F).

2) Place the shift lever in neutral position.

3) Turn the A/C switch to OFF.

4) Turn all the accessory switches to OFF.

5) Open the front hood.

6) Measure the ambient temperature.

7) Read the value of «Intake Air Temp.» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Subtract ambient temperature

from «Intake Air Temp.». Is the

obtained value –10 — 50°C (–18

— 90°F)?

Go to step 14. Check the mass air

flow and intake air

temperature sen-

sor. <Ref. to

FU(STI)-40, Mass

Air Flow and Intake

Air Temperature

Sensor.>

14 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

keep the engine speed at 3,000 rpm. (2 minutes

maximum)

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Depress the clutch pedal.

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.490 V or more?

Go to step 15. Go to step 16.

15 CHECK REAR OXYGEN SENSOR DATA.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), and

rapidly reduce the engine speed from 3,000

rpm.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Depress the clutch pedal.

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value of «Rear O2 Sen-

sor» 0.250 V or less?

Go to step 17. Go to step 16.

16 CHECK REAR OXYGEN SENSOR CONNEC-

TOR AND COUPLING CONNECTOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 18.

Step Check Yes No

15WRX_STI_US_EN.book 377 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-378

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

17 CHECK FRONT OXYGEN (A/F) SENSOR US-

ING REAR OXYGEN SENSOR SIGNAL.

1) Warm up the engine until engine coolant

temperature is higher than 75°C (167°F), then

keep the engine idling for 5 minutes or more.

2) Read the value of «Rear O2 Sensor» using

the Subaru Select Monitor or a general scan

tool.

NOTE:

• Subaru Select Monitor

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

• General scan tool

For detailed operation procedures, refer to the

general scan tool operation manual.

Is the value in «Rear O2 Sen-

sor» kept at 0.250 V or less for 5

minutes or more?

Replace the front

oxygen (A/F) sen-

sor. <Ref. to

FU(STI)-52, Front

Oxygen (A/F) Sen-

sor.>

Go to step 18.

18 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 19. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

19 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 (+) — Chassis ground (–):

Is the voltage 0.2 — 0.5 V? Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

Go to step 20.

20 CHECK OUTPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 25. Go to step 21.

21 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector

on faulty cylinders.

3) Measure the resistance between fuel injec-

tor connector and engine ground on faulty cylin-

ders.

Connector & terminal

#1 (E5) No. 2 — Engine ground:

#2 (E16) No. 2 — Engine ground:

#3 (E6) No. 2 — Engine ground:

#4 (E17) No. 2 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 22. Repair the short

circuit to ground in

harness between

ECM connector

and fuel injector

connector.

Step Check Yes No

15WRX_STI_US_EN.book 378 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-379

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

22 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

Measure the resistance of harness between

ECM connector and fuel injector connector on

faulty cylinders.

Connector & terminal

#1 (B134) No. 10 — (E5) No. 2:

#2 (B134) No. 11 — (E16) No. 2:

#3 (B134) No. 12 — (E6) No. 2:

#4 (B134) No. 13 — (E17) No. 2:

Is the resistance less than 1 Ω? Go to step 23. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and fuel injector

connector

• Poor contact of

coupling connector

23 CHECK FUEL INJECTOR.

Measure the resistance between fuel injector

terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 24. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

24 CHECK POWER SUPPLY LINE.

1) Turn the ignition switch to ON.

2) Measure the voltage between fuel injector

connector of faulty cylinders and engine

ground.

Connector & terminal

#1 (E5) No. 1 (+) — Engine ground (–):

#2 (E16) No. 1 (+) — Engine ground (–):

#3 (E6) No. 1 (+) — Engine ground (–):

#4 (E17) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more? Repair the poor

contact of all con-

nectors in fuel

injector circuit.

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

the main relay and

fuel injector con-

nector on faulty

cylinders

• Poor contact of

coupling connector

• Poor contact of

main relay connec-

tor

25 CHECK HARNESS BETWEEN ECM AND

FUEL INJECTOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from fuel injector

on faulty cylinders.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connec-

tor and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 10 (+) — Chassis ground (–):

#2 (B134) No. 11 (+) — Chassis ground (–):

#3 (B134) No. 12 (+) — Chassis ground (–):

#4 (B134) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and fuel injector

connectors.

Go to step 26.

26 CHECK FUEL INJECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance between fuel injec-

tor terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20 Ω? Go to step 27. Replace the faulty

fuel injector. <Ref.

to FU(STI)-43,

Fuel Injector.>

Step Check Yes No

15WRX_STI_US_EN.book 379 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-380

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

27 CHECK INSTALLATION CONDITION OF

CAMSHAFT POSITION SENSOR/CRANK-

SHAFT POSITION SENSOR.

Is the camshaft position sensor

or crankshaft position sensor

loosely installed?

Tighten the cam-

shaft position sen-

sor or crankshaft

position sensor.

<Ref. to FU(STI)-

35, Camshaft Posi-

tion Sensor.> <Ref.

to FU(STI)-34,

Crankshaft Posi-

tion Sensor.>

Go to step 28.

28 CHECK CRANK SPROCKET.

Remove the timing belt cover. <Ref. to ME(STI)-

50, REMOVAL, Timing Belt Cover.>

Is the crank sprocket rusted or

does it have broken teeth?

Replace the crank

sprocket. <Ref. to

ME(STI)-61, Crank

Sprocket.>

Go to step 29.

29 CHECK INSTALLATION CONDITION OF

TIMING BELT.

Turn the crankshaft using ST, and align the

alignment mark on crank sprocket with align-

ment mark on cylinder block.

ST 499987500 CRANKSHAFT

SOCKET

Is the timing belt dislocated

from its proper position?

Repair the installa-

tion condition of

timing belt. <Ref. to

ME(STI)-51, Tim-

ing Belt.>

Go to step 30.

30 CHECK FUEL LEVEL. Is the fuel meter indication

higher than the “Lower” level?

Go to step 31. Refill the fuel so

that the fuel meter

indication is higher

than the “Lower”

level, and proceed

to the next step. Go

to step 31.

31 CHECK STATUS OF MALFUNCTION INDI-

CATOR LIGHT.

1) Clear the memory using the Subaru Select

Monitor or general scan tool. <Ref. to

EN(STI)(diag)-59, Clear Memory Mode.>

2) Start the engine, and drive the vehicle 10

minutes or more.

Does the malfunction indicator

light illuminate or blink?

Go to step 33. Go to step 32.

32 CHECK CAUSE OF MISFIRE. Was the cause of misfire identi-

fied when the engine is run-

ning?

Finish diagnostics

operation, if the

engine has no

abnormality.

Repair the poor

contact of connec-

tor.

NOTE:

In this case, repair

the following item:

• Poor contact of

ignition coil con-

nector

• Poor contact of

fuel injector con-

nector on faulty

cylinders

• Poor contact of

ECM connector

• Poor contact of

coupling connector

Step Check Yes No

15WRX_STI_US_EN.book 380 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-381

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

33 CHECK AIR INTAKE SYSTEM. Is there any fault in air intake

system?

Repair the air

intake system.

NOTE:

Check the follow-

ing items.

• Are there air

leaks or air suction

caused by loose or

dislocated nuts

and bolts?

• Are there cracks

or any disconnec-

tion of hoses?

Go to step 34.

34 CHECK MISFIRE SYMPTOM.

1) Turn the ignition switch to ON.

2) Check for DTC. <Ref. to EN(STI)(diag)-42,

Read Diagnostic Trouble Code (DTC).>

Does the Subaru Select Moni-

tor or general scan tool indicate

only one DTC?

Go to step 37. Go to step 35.

35 CHECK DTC. Is DTC P0301 and P0303 dis-

played on the Subaru Select

Monitor or general scan tool?

Go to step 38. Go to step 36.

36 CHECK DTC. Is DTC P0302 and P0304 dis-

played on the Subaru Select

Monitor or general scan tool?

Go to step 39. Go to step 40.

37 ONLY ONE CYLINDER. Is there any fault in the cylin-

der?

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

38 GROUP OF #1 AND #3 CYLINDERS. Are there any faults in #1 and

#3 cylinders?

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

• Skipping timing

belt teeth

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

39 GROUP OF #2 AND #4 CYLINDERS. Are there any faults in #2 and

#4 cylinders?

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

• Skipping timing

belt teeth

Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

Step Check Yes No

15WRX_STI_US_EN.book 381 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-382

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

40 CYLINDER AT RANDOM. Is the engine idle rough? Go to DTC P0171.

<Ref. to

EN(STI)(diag)-

158, DTC P0171

SYSTEM TOO

LEAN (BANK 1),

Diagnostic Proce-

dure with Diagnos-

tic Trouble Code

(DTC).>

Repair or replace

faulty parts.

NOTE:

Check the follow-

ing items.

• Spark plug

• Ignition coil

• Fuel injector

• Compression ra-

tio

Step Check Yes No

15WRX_STI_US_EN.book 382 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-383

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FI: DTC P2257 AIR SYSTEM CONTROL "A" CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-211, DTC P2257 AIR SYSTEM CONTROL "A" CIRCUIT

LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 383 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-384

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 384 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-385

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR PUMP RELAY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Remove the secondary air pump relay.

4) Measure the resistance of harness between

ECM connector and secondary air pump relay

connector.

Connector & terminal

(B135) No. 27 — (F9) No. 13:

Is the resistance less than 1 Ω? Go to step 2. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

pump relay con-

nector

• Poor contact of

coupling connector

2 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR PUMP RELAY CONNEC-

TOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 27 — Chassis ground:

Is the resistance 1 MΩ or

more?

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Repair the short

circuit to ground in

harness between

ECM connector

and secondary air

pump relay con-

nector.

15WRX_STI_US_EN.book 385 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-386

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FJ:DTC P2258 AIR SYSTEM CONTROL "A" CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-212, DTC P2258 AIR SYSTEM CONTROL "A" CIRCUIT

HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 386 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-387

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 387 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-388

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR PUMP RELAY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Remove the secondary air pump relay.

4) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 27 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and secondary air

pump relay con-

nector.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 388 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-389

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FK:DTC P2270 O2 SENSOR SIGNAL BIASED/STUCK LEAN (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-213, DTC P2270 O2 SENSOR SIGNAL BIASED/STUCK

LEAN (BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 389 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-390

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK REAR OXYGEN SENSOR CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Connect the connector to ECM.

2) Turn the ignition switch to ON.

3) Measure the voltage between rear oxygen

sensor connector and chassis ground.

Connector & terminal

(T6) No. 3 (+) — Chassis ground (–):

Is the voltage 0.15 V or more? Repair the short

circuit to power in

the harness

between ECM con-

nector and rear

oxygen sensor

connector.

Go to step 4.

4 CHECK EXHAUST SYSTEM.

Check exhaust system parts.

NOTE:

Check the following items.

• Looseness and improper fitting of exhaust

system parts

• Damage (crack, hole etc.) of parts

• Damage (crack, hole etc.) between front oxy-

gen (A/F) sensor and rear oxygen sensor

Is there any fault in exhaust

system?

Repair or replace

faulty parts.

Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

15WRX_STI_US_EN.book 390 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-391

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FL:DTC P2271 O2 SENSOR SIGNAL BIASED/STUCK RICH (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-215, DTC P2271 O2 SENSOR SIGNAL BIASED/STUCK

RICH (BANK 1 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B83B1

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B550

519

B225

T5B19

B134A:

B135B:

B136C:

B137D:

B30

C20

B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

EN-10858

B21

J/C

B83

J/C

101

242322 272625212019

432

698

11 12

B550

B19

SBF-5

ECM

A/F, OXYGEN

SENSOR RELAY

BATTERY

FUSE HOLDER

REAR OXYGEN

SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 391 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-392

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK REAR OXYGEN SENSOR CONNEC-

TOR.

Has water entered the connec-

tor?

Completely

remove any water

inside.

Go to step 2.

2 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

rear oxygen sensor.

3) Measure the resistance of harness between

ECM connector and rear oxygen sensor con-

nector.

Connector & terminal

(B136) No. 20 — (T6) No. 3:

(B135) No. 30 — (T6) No. 4:

Is the resistance less than 1 Ω? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and rear oxygen

sensor connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

REAR OXYGEN SENSOR CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B136) No. 20 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 4. Repair the short

circuit to ground in

harness between

ECM connector

and rear oxygen

sensor connector.

4 CHECK EXHAUST SYSTEM.

Check exhaust system parts.

NOTE:

Check the following items.

• Looseness and improper fitting of exhaust

system parts

• Damage (crack, hole etc.) of parts

• Damage (crack, hole etc.) between front oxy-

gen (A/F) sensor and rear oxygen sensor

Is there any fault in exhaust

system?

Repair or replace

faulty parts.

Replace the rear

oxygen sensor.

<Ref. to FU(STI)-

54, Rear Oxygen

Sensor.>

15WRX_STI_US_EN.book 392 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-393

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FM:DTC P2401 EVAPORATIVE EMISSION SYSTEM LEAK DETECTION PUMP

CONTROL CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-216, DTC P2401 EVAPORATIVE EMISSION SYSTEM

LEAK DETECTION PUMP CONTROL CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 393 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-394

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 27 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 2. Go to step 3.

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary open or

short circuit of har-

ness or temporary

poor contact of

connector may be

the cause.

3 CHECK POWER SUPPLY TO LEAK CHECK

VALVE ASSEMBLY.

Measure the voltage between the leak check

valve assembly connector and engine ground.

Connector & terminal

(R400) No. 3 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 4. Repair the power

supply circuit.

4 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

the leak check valve assembly.

3) Measure the resistance between leak check

valve assembly and chassis ground.

Connector & terminal

(R400) No. 4 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and leak check

valve assembly

connector.

5 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

Measure the resistance of harness between

ECM connector and the leak check valve

assembly connector.

Connector & terminal

(B137) No. 27 — (R400) No. 4:

Is the resistance less than 1 Ω? Go to step 6. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the leak check

valve assembly

connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 394 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-395

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK LEAK CHECK VALVE ASSEMBLY.

Check the vacuum pump of the leak check valve

assembly. <Ref. to EC(STI)-47, CHECK VAC-

UUM PUMP, INSPECTION, Leak Check Valve

Assembly.>

Is the vacuum pump of the leak

check valve assembly OK?

Repair the poor

contact in the leak

check valve

assembly connec-

tor.

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Step Check Yes No

15WRX_STI_US_EN.book 395 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-396

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FN:DTC P2402 EVAPORATIVE EMISSION SYSTEM LEAK DETECTION PUMP

CONTROL CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-217, DTC P2402 EVAPORATIVE EMISSION SYSTEM

LEAK DETECTION PUMP CONTROL CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 396 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-397

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the leak

check valve assembly.

3) Turn the ignition switch to ON.

4) Measure the voltage between leak check

valve assembly and chassis ground.

Connector & terminal

(R400) No. 4 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and leak check

valve assembly

connector.

Go to step 2.

2 CHECK LEAK CHECK VALVE ASSEMBLY.

1) Turn the ignition switch to OFF.

2) Check the vacuum pump of the leak check

valve assembly. <Ref. to EC(STI)-47, CHECK

VACUUM PUMP, INSPECTION, Leak Check

Valve Assembly.>

Is the vacuum pump of the leak

check valve assembly OK?

Repair the poor

contact in the leak

check valve

assembly connec-

tor.

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

15WRX_STI_US_EN.book 397 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-398

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FO:DTC P2404 EVAPORATIVE EMISSION SYSTEM LEAK DETECTION PUMP

SENSE CIRCUIT RANGE/PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-218, DTC P2404 EVAPORATIVE EMISSION SYSTEM

LEAK DETECTION PUMP SENSE CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC)

Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 398 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-399

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK ELCM PUMP.

Operate the ELCM pump using the Subaru

Select Monitor.

NOTE:

For detailed procedures, refer to “System Oper-

ation Check Mode”. <Ref. to EN(STI)(diag)-60,

System Operation Check Mode.>

Does the ELCM pump operate? Go to step 6. Go to step 3.

3 CHECK POWER SUPPLY OF LEAK CHECK

VALVE ASSEMBLY.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the leak

check valve assembly.

3) Turn the ignition switch to ON.

4) Measure the voltage between the leak

check valve assembly connector and chassis

ground.

Connector & terminal

(R400) No. 3 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

the main relay and

the leak check

valve assembly

connector

• Poor contact of

main relay connec-

tor

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and the leak check valve

assembly connector.

Connector & terminal

(B137) No. 27 — (R400) No. 4:

Is the resistance less than 1 Ω? Go to step 5. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the leak check

valve assembly

connector

• Poor contact of

coupling connector

5 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Measure the resistance of harness between

ECM connector and chassis ground.

Connector & terminal

(B137) No. 27 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Repair the short

circuit to ground in

harness between

ECM connector

and leak check

valve assembly

connector.

15WRX_STI_US_EN.book 399 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-400

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK ELCM SWITCHING VALVE.

Operate the ELCM switching valve using the

Subaru Select Monitor.

NOTE:

For detailed procedures, refer to “System Oper-

ation Check Mode”. <Ref. to EN(STI)(diag)-60,

System Operation Check Mode.>

Does the ELCM switching valve

operate?

Go to step 10. Go to step 7.

7 CHECK POWER SUPPLY OF LEAK CHECK

VALVE ASSEMBLY.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the leak

check valve assembly.

3) Turn the ignition switch to ON.

4) Measure the voltage between the leak

check valve assembly connector and chassis

ground.

Connector & terminal

(R400) No. 5 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 8. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

the main relay and

the leak check

valve assembly

connector

• Poor contact of

main relay connec-

tor

• Poor contact of

coupling connector

8 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and the leak check valve

assembly connector.

Connector & terminal

(B135) No. 4 — (R400) No. 1:

Is the resistance less than 1 Ω? Go to step 9. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the leak check

valve assembly

connector

• Poor contact of

coupling connector

9 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Measure the resistance of harness between

ECM connector and chassis ground.

Connector & terminal

(B135) No. 4 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Repair the short

circuit to ground in

harness between

ECM connector

and leak check

valve assembly

connector.

10 CHECK EVAPORATIVE EMISSION CON-

TROL SYSTEM.

Perform drive cycle I. <Ref. to EN(STI)(diag)-

56, DRIVE CYCLE I, PROCEDURE, Drive

Cycle.>

Is DTC P2404 displayed on the

display?

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Step Check Yes No

15WRX_STI_US_EN.book 400 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-401

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FP:DTC P2419 EVAPORATIVE EMISSION SYSTEM SWITCHING VALVE CON-

TROL CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-219, DTC P2419 EVAPORATIVE EMISSION SYSTEM

SWITCHING VALVE CONTROL CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 401 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-402

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground.

Connector & terminal

(B135) No. 4 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 2. Go to step 3.

2 CHECK FOR POOR CONTACT.

Check for poor contact of ECM connector.

Is there poor contact of ECM

connector?

Repair the poor

contact of ECM

connector.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary open or

short circuit of har-

ness or temporary

poor contact of

connector may be

the cause.

3 CHECK POWER SUPPLY TO LEAK CHECK

VALVE ASSEMBLY.

Measure the voltage between the leak check

valve assembly connector and engine ground.

Connector & terminal

(R400) No. 5 (+) — Engine ground (–):

Is the voltage 10 V or more? Go to step 4. Repair the power

supply circuit.

4 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM and

the leak check valve assembly.

3) Measure the resistance between leak check

valve assembly and chassis ground.

Connector & terminal

(R400) No. 1 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the short

circuit to ground in

harness between

ECM connector

and leak check

valve assembly

connector.

5 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

Measure the resistance of harness between

ECM connector and the leak check valve

assembly connector.

Connector & terminal

(B135) No. 4 — (R400) No. 1:

Is the resistance less than 1 Ω? Go to step 6. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and the leak check

valve assembly

connector

• Poor contact of

coupling connector

15WRX_STI_US_EN.book 402 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-403

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK LEAK CHECK VALVE ASSEMBLY.

Check the switching valve of the leak check

valve assembly. <Ref. to EC(STI)-45, CHECK

SWITCHING VALVE, INSPECTION, Leak

Check Valve Assembly.>

Is the switching valve of the

leak check valve assembly OK?

Repair the poor

contact in the leak

check valve

assembly connec-

tor.

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

Step Check Yes No

15WRX_STI_US_EN.book 403 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-404

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FQ:DTC P2420 EVAPORATIVE EMISSION SYSTEM SWITCHING VALVE CON-

TROL CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-220, DTC P2420 EVAPORATIVE EMISSION SYSTEM

SWITCHING VALVE CONTROL CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

19 20

1234 567

10 11 12 13 14 15 16 17 18

B97

B83

456

123

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

2524

987

17 18 19 20

21 22 23

29 3231

1234

2726

33 34 35

B136C:

B135B:

B136C:

B137D:

EN-10868

R1B97

B83

J/C

R400

1234

5678

R400

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B550

216

B220

D27

B30

B22

C21

101

242322 272625212019

432

698

11 12

B550

ECM

SBF-7

VACUUM PUMP

MAIN RELAY

BATTERY

FUSE HOLDER

LEAK CHECK VALVE ASSY

SWITCHING VALVE

PRESSURE SENSOR

: TERMINAL No. OPTIONAL ARRANGEMENT

15WRX_STI_US_EN.book 404 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-405

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK HARNESS BETWEEN ECM AND

LEAK CHECK VALVE ASSEMBLY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the leak

check valve assembly.

3) Turn the ignition switch to ON.

4) Measure the voltage between leak check

valve assembly and chassis ground.

Connector & terminal

(R400) No. 1 (+) — Chassis ground (–):

Is the voltage 10 V or more? Repair the short

circuit to power in

harness between

ECM connector

and leak check

valve assembly

connector.

Go to step 2.

2 CHECK LEAK CHECK VALVE ASSEMBLY.

1) Turn the ignition switch to OFF.

2) Check the switching valve of the leak check

valve assembly. <Ref. to EC(STI)-45, CHECK

SWITCHING VALVE, INSPECTION, Leak

Check Valve Assembly.>

Is the switching valve of the

leak check valve assembly OK?

Repair the poor

contact in the leak

check valve

assembly connec-

tor.

Replace the leak

check valve

assembly. <Ref. to

EC(STI)-30, Leak

Check Valve

Assembly.>

15WRX_STI_US_EN.book 405 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-406

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FR:DTC P2431 SECONDARY AIR INJECTION SYSTEM AIR FLOW /PRESSURE

SENSOR CIRCUIT RANGE/PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-221, DTC P2431 SECONDARY AIR INJECTION SYSTEM

AIR FLOW /PRESSURE SENSOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC)

Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check the appro-

priate DTC using

the “List of Diag-

nostic Trouble

Code (DTC)”.

<Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Go to step 2.

2 CHECK CURRENT DATA.

1) Turn the ignition switch to ON (engine OFF).

2) Using the Subaru Select Monitor, read the

values in «Sec. Air Piping Pressure», «Mani.

Absolute Pressure» and «Atmosphere Pres-

sure», and compare them with actual atmo-

spheric pressure.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Does the displayed value differ

from the actual atmospheric

pressure by 200 mmHg (27

kPa, 8 inHg, 3.9 psig) or more?

Replace the sec-

ondary air combi-

nation valve (with

built-in pressure

sensor). <Ref. to

EC(STI)-54, Sec-

ondary Air Combi-

nation Valve.>

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 406 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-407

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FS:DTC P2432 SECONDARY AIR INJECTION SYSTEM AIR FLOW /PRESSURE

SENSOR CIRCUIT LOW

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-222, DTC P2432 SECONDARY AIR INJECTION SYSTEM

AIR FLOW /PRESSURE SENSOR CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 407 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-408

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 408 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-409

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Turn the ignition switch to ON.

2) Read the value of «Sec. Air Piping Pres-

sure» using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Sec. Air Piping

Pressure» less than 53.3 kPa

(400 mmHg, 15.8 inHg)?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK POWER SUPPLY OF SECONDARY

AIR COMBINATION VALVE.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the second-

ary air combination valve LH.

3) Turn the ignition switch to ON.

4) Measure the voltage between the second-

ary air combination valve LH connector and

chassis ground.

Connector & terminal

(E40) No. 1 (+) — Chassis ground (–):

Is the voltage 4.5 V or more? Go to step 3. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

LH connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

3 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from ECM.

3) Measure the resistance of harness between

ECM connector and secondary air combination

valve LH connector.

Connector & terminal

(B137) No. 9 — (E40) No. 2:

Is the resistance less than 1 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

LH connector

• Poor contact of

coupling connector

4 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

CONNECTOR.

Measure the resistance between ECM connec-

tor and chassis ground.

Connector & terminal

(B137) No. 9 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 5. Repair the ground

short circuit in har-

ness between

ECM connector

and secondary air

combination valve

LH connector.

5 CHECK FOR POOR CONTACT.

Check for poor contact of the ECM and second-

ary air combination valve LH connector.

Is there poor contact of the

ECM or secondary air combi-

nation valve LH connector?

Repair the poor

contact of the ECM

or secondary air

combination valve

LH connector.

Replace the sec-

ondary air combi-

nation valve LH.

<Ref. to EC(STI)-

54, Secondary Air

Combination

Valve.>

15WRX_STI_US_EN.book 409 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-410

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FT:DTC P2433 SECONDARY AIR INJECTION SYSTEM AIR FLOW /PRESSURE

SENSOR CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-223, DTC P2433 SECONDARY AIR INJECTION SYSTEM

AIR FLOW /PRESSURE SENSOR CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 410 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-411

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 411 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-412

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK CURRENT DATA.

1) Turn the ignition switch to ON.

2) Read the value of «Sec. Air Piping Pres-

sure» using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Sec. Air Piping

Pressure» 133.3 kPa (1,000

mmHg, 39.4 inHg) or more?

Go to step 2. Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

2 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the second-

ary air combination valve LH.

3) Turn the ignition switch to ON.

4) Read the value of «Sec. Air Piping Pres-

sure» using Subaru Select Monitor.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the value of «Sec. Air Piping

Pressure» 133.3 kPa (1,000

mmHg, 39.4 inHg) or more?

Repair the short

circuit to power in

harness between

ECM connector

and secondary air

combination valve

LH connector.

Go to step 3.

3 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

CONNECTOR.

1) Turn the ignition switch to OFF.

2) Measure the resistance of the harness

between the secondary air combination valve

LH connector and engine ground.

Connector & terminal

(E40) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step 4. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

LH connector

• Poor contact of

ECM connector

• Poor contact of

coupling connector

4 CHECK FOR POOR CONTACT.

Check for poor contact of the secondary air

combination valve LH connector.

Is there poor contact of the sec-

ondary air combination valve

LH connector?

Repair the poor

contact of the sec-

ondary air combi-

nation valve LH

connector.

Replace the sec-

ondary air combi-

nation valve LH.

<Ref. to EC(STI)-

54, Secondary Air

Combination

Valve.>

15WRX_STI_US_EN.book 412 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-413

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FU:DTC P2440 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK OPEN (BANK1)

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-224, DTC P2440 SECONDARY AIR INJECTION SYSTEM

SWITCHING VALVE STUCK OPEN (BANK1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 413 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-414

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 414 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-415

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK SECONDARY AIR COMBINATION

VALVE FUSE.

Check if the secondary air combination valve

fuse (10 A) is blown out.

Is the fuse blown out? Go to step 2. Go to step 3.

2 CHECK HARNESS BETWEEN FUSE BOX

AND SECONDARY AIR COMBINATION

VALVE RH CONNECTOR.

1) Remove the secondary air combination

valve fuse (10 A) from the fuse box.

2) Disconnect the connectors from the sec-

ondary air combination valve RH and the sec-

ondary air combination valve LH.

3) Measure the resistance between the sec-

ondary air combination valve fuse, secondary

air combination valve RH connector, secondary

air combination valve LH connector and the

chassis ground.

Connector & terminal

(F9) No. 5 — Chassis ground:

(E41) No. 2 — Chassis ground:

(E40) No. 6 — Chassis ground:

Is the resistance 1 MΩ or

more?

Replace the fuse

with a new part,

and connect the

secondary air com-

bination valve RH

connector and the

secondary air com-

bination valve LH

connector.

Go to step 3.

Repair the short

circuit to ground in

harness between

the fuse box and

the secondary air

combination valve

RH connector and

the secondary air

combination valve

LH connector.

3 CHECK SECONDARY AIR COMBINATION

VALVE RH OPERATION.

1) Install the delivery mode fuse.

2) Turn the ignition switch to ON.

3) Perform operation check for the secondary

air combination valve RH using the Subaru

Select Monitor.

NOTE:

For detailed procedures, refer to “System Oper-

ation Check Mode”. <Ref. to EN(STI)(diag)-60,

System Operation Check Mode.>

Does the secondary air combi-

nation valve RH repeatedly

switch to ON and OFF?

Go to step 4. Go to step 6.

4 CHECK DUCT BETWEEN SECONDARY AIR

PUMP AND SECONDARY AIR COMBINA-

TION VALVE RH.

Check the duct between the secondary air

pump and secondary air combination valve RH.

Is there damage, clog or dis-

connection of the duct?

Replace, clean or

connect the duct.

Go to step 5.

5 CHECK PIPE BETWEEN SECONDARY AIR

COMBINATION VALVE RH AND CYLINDER

HEAD.

Check the pipe between the secondary air com-

bination valve RH and cylinder head.

Is there damage, clog or dis-

connection of the pipe?

Replace, clean or

connect the pipe.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

15WRX_STI_US_EN.book 415 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-416

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6 CHECK POWER SUPPLY TO SECONDARY

AIR COMBINATION VALVE RH.

1) Disconnect the connector from the second-

ary air combination valve RH.

2) In the condition of step 3, measure the volt-

age between secondary air combination valve

RH connector and chassis ground.

Connector & terminal

(E41) No. 2 (+) — Chassis ground (–):

Does the voltage repeatedly

change between 10 V and 0 V?

Replace the sec-

ondary air combi-

nation valve RH.

<Ref. to EC(STI)-

54, Secondary Air

Combination

Valve.>

Go to step 7.

7 CHECK HARNESS BETWEEN SECONDARY

AIR COMBINATION VALVE RH AND CHAS-

SIS GROUND.

Measure the resistance between the secondary

air combination valve RH connector and chas-

sis ground.

Connector & terminal

(E41) No. 1 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 8. Repair the open

circuit in harness

between second-

ary air combination

valve RH connec-

tor and chassis

ground.

8 CHECK HARNESS BETWEEN SECONDARY

AIR COMBINATION VALVE RELAY 2 AND

SECONDARY AIR COMBINATION VALVE

RH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Remove the secondary air combination

valve relay 2 from the relay box.

3) Measure the resistance of the harness

between secondary air combination valve relay

2 connector and secondary air combination

valve RH connector.

Connector & terminal

(F9) No. 8 — (E41) No. 2:

Is the resistance less than 1 Ω? Go to step 9. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

secondary air com-

bination valve re-

lay 2 connector

and secondary air

combination valve

RH connector

• Poor contact of

coupling connector

9 CHECK SECONDARY AIR COMBINATION

VALVE RELAY 2.

1) Connect the battery to terminals No. 9 and

No. 10 of the secondary air combination valve

relay 2.

2) Measure the resistance between the sec-

ondary air combination valve relay 2 terminals.

Terminals

No. 7 — No. 8:

Is the resistance less than 1 Ω? Go to step 10. Replace the sec-

ondary air combi-

nation valve relay

2. <Ref. to

EN(STI)(diag)-8,

Electrical Compo-

nent Location.>

10 CHECK SECONDARY AIR COMBINATION

VALVE RELAY 2.

Measure the resistance between the secondary

air combination valve relay 2 terminals with the

battery disconnected.

Terminals

No. 7 — No. 8:

Is the resistance 1 MΩ or

more?

Go to step 11. Replace the sec-

ondary air combi-

nation valve relay

2. <Ref. to

EN(STI)(diag)-8,

Electrical Compo-

nent Location.>

11 CHECK SECONDARY AIR COMBINATION

VALVE RELAY 2 POWER SUPPLY.

1) Turn the ignition switch to ON.

2) Measure the voltage between the second-

ary air combination valve relay 2 connector and

chassis ground.

Connector & terminal

(F9) No. 7 (+) — Chassis ground (–):

(F9) No. 10 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 12. Repair the open or

ground short circuit

of power supply

circuit.

Step Check Yes No

15WRX_STI_US_EN.book 416 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-417

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

12 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 2 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the ECM connector.

3) Measure the resistance of harness between

ECM connector and secondary air combination

valve relay 2 connector.

Connector & terminal

(B135) No. 20 — (F9) No. 9:

Is the resistance less than 1 Ω? Go to step 13. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

relay 2 connector

• Poor contact of

coupling connector

13 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 2 CONNECTOR.

Measure the resistance between the secondary

air combination valve relay 2 connector and

chassis ground.

Connector & terminal

(F9) No. 9 — Chassis ground:

Is the resistance 1 MΩ or

more?

Go to step 14. Repair the short

circuit to ground in

harness between

ECM connector

and secondary air

combination valve

relay 2 connector.

14 CHECK SECONDARY AIR COMBINATION

VALVE LH OPERATION.

1) Install the delivery mode fuse.

2) Turn the ignition switch to ON.

3) Perform operation check for the secondary

air combination valve LH using the Subaru

Select Monitor.

NOTE:

For detailed procedures, refer to “System Oper-

ation Check Mode”. <Ref. to EN(STI)(diag)-60,

System Operation Check Mode.>

Does the secondary air combi-

nation valve LH repeatedly

switch to ON and OFF?

Go to step 15. Go to step 17.

15 CHECK DUCT BETWEEN SECONDARY AIR

PUMP AND SECONDARY AIR COMBINA-

TION VALVE LH.

Check the duct between the secondary air

pump and secondary air combination valve LH.

Is there damage, clog or dis-

connection of the duct?

Replace, clean or

connect the duct.

Go to step 16.

16 CHECK PIPE BETWEEN SECONDARY AIR

COMBINATION VALVE LH AND CYLINDER

HEAD.

Check the pipe between the secondary air com-

bination valve LH and cylinder head.

Is there damage, clog or dis-

connection of the pipe?

Replace, clean or

connect the pipe.

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, tem-

porary poor con-

tact of connector,

temporary open or

short circuit of har-

ness may be the

cause.

Step Check Yes No

15WRX_STI_US_EN.book 417 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-418

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

17 CHECK POWER SUPPLY TO SECONDARY

AIR COMBINATION VALVE LH.

1) Disconnect the connector from the second-

ary air combination valve LH.

2) In the condition of step 14, measure the volt-

age between secondary air combination valve

LH connector and chassis ground.

Connector & terminal

(E40) No. 6 (+) — Chassis ground (–):

Does the voltage repeatedly

change between 10 V and 0 V?

Replace the sec-

ondary air combi-

nation valve LH.

<Ref. to EC(STI)-

54, Secondary Air

Combination

Valve.>

Go to step 18.

18 CHECK HARNESS BETWEEN SECONDARY

AIR COMBINATION VALVE LH AND CHAS-

SIS GROUND.

Measure the resistance between the secondary

air combination valve LH connector and chassis

ground.

Connector & terminal

(E40) No. 4 — Chassis ground:

Is the resistance less than 5 Ω? Go to step 19. Repair the open

circuit in harness

between second-

ary air combination

valve LH connector

and chassis

ground.

19 CHECK HARNESS BETWEEN SECONDARY

AIR COMBINATION VALVE RELAY 1 AND

SECONDARY AIR COMBINATION VALVE

LH CONNECTOR.

1) Turn the ignition switch to OFF.

2) Remove the secondary air combination

valve relay 1 from the relay box.

3) Measure the resistance of the harness

between the secondary air combination valve

relay 1 and secondary air combination valve LH

connector.

Connector & terminal

(F9) No. 3 — (E40) No. 6:

Is the resistance less than 1 Ω? Go to step 20. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

secondary air com-

bination valve re-

lay 1 connector

and secondary air

combination valve

LH connector

• Poor contact of

coupling connector

20 CHECK SECONDARY AIR COMBINATION

VALVE RELAY 1.

1) Connect the battery to terminals No. 1 and

No. 2 of the secondary air combination valve

relay 1.

2) Measure the resistance between the sec-

ondary air combination valve relay 1 terminals.

Terminals

No. 3 — No. 4:

Is the resistance less than 1 Ω? Go to step 21. Replace the sec-

ondary air combi-

nation valve relay

1. <Ref. to

EN(STI)(diag)-8,

Electrical Compo-

nent Location.>

21 CHECK SECONDARY AIR COMBINATION

VALVE RELAY 1.

Measure the resistance between the secondary

air combination valve relay 1 terminals with the

battery disconnected.

Terminals

No. 3 — No. 4:

Is the resistance 1 MΩ or

more?

Go to step 22. Replace the sec-

ondary air combi-

nation valve relay

1. <Ref. to

EN(STI)(diag)-8,

Electrical Compo-

nent Location.>

22 CHECK SECONDARY AIR COMBINATION

VALVE RELAY 1 POWER SUPPLY.

1) Turn the ignition switch to ON.

2) Measure the voltage between the second-

ary air combination valve relay 1 connector and

chassis ground.

Connector & terminal

(F9) No. 4 (+) — Chassis ground (–):

(F9) No. 1 (+) — Chassis ground (–):

Is the voltage 10 V or more? Go to step 23. Repair the open or

ground short circuit

of power supply

circuit.

Step Check Yes No

15WRX_STI_US_EN.book 418 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-419

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FV:DTC P2441 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK CLOSED (BANK1)

NOTE:

For the diagnostic procedure, refer to DTC P2440. <Ref. to EN(STI)(diag)-413, DTC P2440 SECONDARY

AIR INJECTION SYSTEM SWITCHING VALVE STUCK OPEN (BANK1), Diagnostic Procedure with Diag-

nostic Trouble Code (DTC).>

FW:DTC P2442 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK OPEN (BANK2)

NOTE:

For the diagnostic procedure, refer to DTC P2440. <Ref. to EN(STI)(diag)-413, DTC P2440 SECONDARY

AIR INJECTION SYSTEM SWITCHING VALVE STUCK OPEN (BANK1), Diagnostic Procedure with Diag-

nostic Trouble Code (DTC).>

FX:DTC P2443 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK CLOSED (BANK2)

NOTE:

For the diagnostic procedure, refer to DTC P2440. <Ref. to EN(STI)(diag)-413, DTC P2440 SECONDARY

AIR INJECTION SYSTEM SWITCHING VALVE STUCK OPEN (BANK1), Diagnostic Procedure with Diag-

nostic Trouble Code (DTC).>

23 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 1 CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the ECM connector.

3) Measure the resistance of harness between

ECM connector and secondary air combination

valve relay 1 connector.

Connector & terminal

(B135) No. 8 — (F9) No. 2:

Is the resistance less than 1 Ω? Go to step 24. Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

• Open circuit in

harness between

ECM connector

and secondary air

combination valve

relay 1 connector

• Poor contact of

coupling connector

24 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR COMBINATION VALVE

RELAY 1 CONNECTOR.

Measure the resistance between the secondary

air combination valve relay 1 connector and

chassis ground.

Connector & terminal

(F9) No. 2 — Chassis ground:

Is the resistance 1 MΩ or

more?

Repair the poor

contact of ECM

connector.

Repair the short

circuit to ground in

harness between

ECM connector

and secondary air

combination valve

relay 1 connector.

Step Check Yes No

15WRX_STI_US_EN.book 419 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-420

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FY:DTC P2444 SECONDARY AIR INJECTION SYSTEM PUMP STUCK ON

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-225, DTC P2444 SECONDARY AIR INJECTION SYSTEM

PUMP STUCK ON, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

15WRX_STI_US_EN.book 420 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-421

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

ECM

M/B

F37

B: B143

E40

B143B:

19 20

1234 567

10 11 12 13 14 15 16 17 18

F37A:

1234

56789

10 11 12 13 14 15 16 17 18 19 20

F11

34 7

12 13

E41

123

456

E40

B220

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

A13

B21

B550

216

B220

60A

10A

B10

B20

A5B2

A17B13

A20

A18B12

B4 A8

A19

A29

B27

B20

B137D:

B135B:

B134A:

A16

B14

E41 F11

EN-10867

101

242322 272625212019

432

698

11 12

B550

SBF-7

SECONDARY

AIR PUMP

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR PUMP RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR COMBINATION

VALVE RELAY 1

MAIN SBF

MAIN RELAY

BATTERY

FUSE HOLDER

RELAY HOLDER

SECONDARY AIR

COMBINATION VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

15WRX_STI_US_EN.book 421 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-422

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK SECONDARY AIR PIPING PRES-

SURE.

1) Turn the ignition switch to ON.

2) Using the Subaru Select Monitor, read the

value of «Sec. Air Piping Pressure», and com-

pare with the actual atmospheric pressure.

NOTE:

For detailed operation procedures, refer to

“READ CURRENT DATA FOR ENGINE”. <Ref.

to EN(STI)(diag)-36, Subaru Select Monitor.>

Is the difference between «Sec.

Air Piping Pressure» and atmo-

spheric pressure 50 mmHg (6.7

kPa, 2.0 inHg, 0.97 psig) or

less?

Go to step 2. Replace the sec-

ondary air combi-

nation valve LH.

<Ref. to EC(STI)-

54, Secondary Air

Combination

Valve.>

2 CHECK HARNESS BETWEEN ECM AND

SECONDARY AIR PUMP RELAY CONNEC-

TOR.

1) Turn the ignition switch to OFF.

2) Remove the secondary air pump relay from

the relay holder.

3) Measure the resistance between the sec-

ondary air pump relay connector and engine

ground terminals.

Connector & terminal

(F9) No. 13 — Engine ground:

Is the resistance 1 MΩ or

more?

Go to step 3. Repair the short

circuit to ground in

harness between

ECM connector

and secondary air

pump relay con-

nector, and go to

the next step. Go to

step 3.

3 CHECK SECONDARY AIR PUMP FUSE.

1) Disconnect the secondary air pump con-

nector.

2) Install the secondary air pump relay to the

relay holder.

3) Check the MAIN SBF and the secondary air

pump fuse (60 A) for blown out.

Is the fuse blown out? Replace the fuse

with a new part,

and go to the next

step. Go to step 4.

Go to step 4.

4 CHECK SECONDARY AIR PUMP POWER

SUPPLY.

1) Disconnect the positive (+) terminal after

disconnecting the negative (–) terminal of bat-

tery.

2) Measure the resistance between secondary

air pump connector and battery cable positive

terminal.

Connector & terminal

(F11) No. 2 — battery cable positive ter-

minal:

Is the resistance 1 MΩ or

more?

Go to step 6. Go to step 5.

5 CHECK SECONDARY AIR PUMP RELAY.

1) Remove the secondary air pump relay from

the relay holder.

2) Measure the resistance between the sec-

ondary air pump relay terminals.

Terminals

No. 11 — No. 14:

Is the resistance 1 MΩ or

more?

Repair the short

circuit to power of

the secondary air

pump, and go to

the next step. Go to

step 6.

Replace the sec-

ondary air pump

relay. <Ref. to

EN(STI)(diag)-8,

LOCATION, Elec-

trical Component

Location.> After

replacement, go to

the next step. Go to

step 6.

6 CHECK SECONDARY AIR PUMP.

Check the appearance of secondary air pump

and the condition of impeller.

Is the secondary air pump free

from deformation, cracks and

other damages? And does the

impeller rotate smoothly?

End. Replace the sec-

ondary air pump.

<Ref. to EC(STI)-

53, Secondary Air

Pump.>

15WRX_STI_US_EN.book 422 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-423

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FZ:DTC P2530 IGNITION SWITCH RUN POSITION CIRCUIT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(STI)-226, DTC P2530 IGNITION SWITCH RUN POSITION CIR-

CUIT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EJ (WITHOUT PUSH BUTTON START) <Ref. to WI-198, EN-

GINE TYPE EJ (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

• Engine Electrical System ENGINE TYPE EJ (WITH PUSH BUTTON START) <Ref. to WI-218, ENGINE

TYPE EJ (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

B72

B550

216

B550

1024

B220

B134A:

B135B:

B136C:

B137D:

B21

C30

B13

B220 B225

10 11

14 15

19 21 22

32 33

28262423

36 37

41 43 44

567

2422 23 25

11 12 13 14 15

26 27

16 17 18 19

20 21

29 30 31 32 33 34 35

B135B:

567

22 23

11 12 13 14 15

24 25

16 17

18 19 20 21

27 28 29 30 31

B137D:

1610 11 12 13 14 15

987

17 18 19 20

21 22

29 3231

1234

2726

33 34 35

B136C:

56 7

2422 23 25

11 12 13 14 15

26 27

16 17

18 19 20 21

33 3429

3230 31

B134A:

B21

123456789

10 11

12 13 14 15 16 17 18 19 20

21 22

23 24 25 26 27 28 29 30 31 32 33

34 35

42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45 46 47

B225

36 37

EN-10853

B72

7856

3412

101

242322 272625212019

432

698

11 12

B550

SBF-7

SBF-6

ECM

: WITHOUT PUSH BUTTON START

: WITH PUSH BUTTON START

IG RELAY 1

(PUSH BUTTON

START)

BATTERY

MAIN

RELAY

FUSE

HOLDER

FUSE

HOLDER

M/B No. 13

F/B No. 12

IGNITION

SWITCH

MAIN SBF

15WRX_STI_US_EN.book 423 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-424

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step Check Yes No

1 CHECK ECM CONNECTOR.

Check the connecting condition of ECM con-

nector.

Is the ECM connector correctly

connected?

Go to step 2. Connect the ECM

connector cor-

rectly.

2 CHECK INPUT VOLTAGE OF ECM.

1) Turn the ignition switch to ON.

2) Measure the voltage between ECM connec-

tor and chassis ground while wiggling the har-

ness between ECM connector and ignition

switch connector (for models without push but-

ton start), or between ECM connector and IG

relay 1 (push button start) connector (for mod-

els with push button start).

Connector & terminal

(B136) No. 30 (+) — Chassis ground (–):

Is the voltage 8 V or more all the

time?

Even if DTC is

detected, the cir-

cuit has returned to

a normal condition

at this time. Repro-

duce the failure,

and then perform

the diagnosis

again.

NOTE:

In this case, the fol-

lowing items may

be the cause of

fault.

Model without

push button start

• Open or short

circuit to ground

in harness be-

tween ECM

connector and

ignition switch

connector

• Poor contact

of ignition

switch connec-

tor

• Poor contact

of ignition

switch

Model with push

button start

• Open circuit

or short circuit

to ground in har-

ness between

ECM connector

and IG relay 1

(push button

start) connector

• Poor contact

in IG relay 1

(push button

start) connector

• Poor contact

in IG relay 1

(push button

start)

Repair the harness

and connector.

NOTE:

In this case, repair

the following item:

Model without

push button start

• Open or short

circuit to ground in

harness between

ECM connector

and ignition switch

connector

• Poor contact of

ignition switch con-

nector

• Poor contact of

ignition switch

• Faulty fuse (F/B

No. 12)

Model with push

button start

• Open circuit or

short circuit to

ground in harness

between ECM con-

nector and IG relay

1 (push button

start) connector

• Poor contact in

IG relay 1 (push

button start) con-

nector

• Poor contact in

IG relay 1 (push

button start)

• Faulty fuse (F/B

No. 12)

15WRX_STI_US_EN.book 424 ページ２０１５年２月１３日　金曜日　午前１１時２０分

EN(STI)(diag)-425

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

GA:DTC P2610 ECM/PCM INTERNAL ENGINE OFF TIMER PERFORMANCE

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(STI)-227, DTC P2610 ECM/PCM INTERNAL ENGINE OFF TIM-

ER PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(STI)(diag)-59, OP-

ERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(STI)(diag)-43, PROCEDURE, In-

spection Mode.>.

GB:DTC U0073 CONTROL MODULE COMMUNICATION BUS OFF

NOTE:

For the diagnostic procedure, refer to LAN section. <Ref. to LAN(diag)-2, Basic Diagnostic Procedure.>

GC:DTC U0122 CAN (VDC) DATA NOT LOADED

NOTE:

For the diagnostic procedure, refer to LAN section. <Ref. to LAN(diag)-2, Basic Diagnostic Procedure.>

GD:DTC U0155 LOST COMMUNICATION WITH INSTRUMENT PANEL CLUSTER

(IPC) CONTROL MODULE

NOTE:

For the diagnostic procedure, refer to LAN section. <Ref. to LAN(diag)-2, Basic Diagnostic Procedure.>

GE:DTC U0416 CAN (VDC) DATA ABNORMAL

NOTE:

For the diagnostic procedure, refer to LAN section. <Ref. to LAN(diag)-2, Basic Diagnostic Procedure.>

GF:DTC U0423 INVALID DATA RECEIVED FROM INSTRUMENT PANEL CLUS-

TER CONTROL MODULE

NOTE:

For the diagnostic procedure, refer to LAN section. <Ref. to LAN(diag)-2, Basic Diagnostic Procedure.>

Step Check Yes No

1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check DTC using

“List of Diagnostic

Trouble Code

(DTC)”. <Ref. to

EN(STI)(diag)-86,

List of Diagnostic

Trouble Code

(DTC).>

Replace the ECM.

<Ref. to FU(STI)-

56, Engine Control

Module (ECM).>

NOTE:

The soak timer IC

is built into the

ECM.

15WRX_STI_US_EN.book 425 ページ２０１５年２月１３日　金曜日　午前１１時２０分